Open Encyclopedia

The AI Glossary

Essential technical terminology explained at the highest level of clarity. Designed for researchers, students, and human-centered education.

173 termsSearch + alphabet filterPlain-language definitions

Showing 173 matching terms.

AGI (Artificial General Intelligence)

A hypothetical AI system that can perform most intellectual tasks at a human level across many domains.

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AI Agent

A software system that can observe, reason, and take actions to achieve a goal, often using tools and memory.

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AI Alignment

The work of making AI systems behave according to human intentions, values, and safety constraints.

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AI Governance

Policies, standards, and oversight mechanisms that guide how AI is developed and used in society.

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AI Safety

A field focused on reducing harmful behavior, failures, and misuse risks in AI systems.

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Algorithm

A defined set of rules or steps that a computer follows to solve a problem or complete a task.

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Algorithmic Bias

Systematic unfairness in model outputs caused by skewed data, assumptions, or modeling choices.

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Algorithmic Transparency

How clearly an AI system's logic, data sources, and limitations are documented and understandable.

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Annotation

Human-added labels or metadata used to train or evaluate machine learning models.

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API (Application Programming Interface)

A structured way for one software system to send requests to and receive responses from another system.

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Artificial Intelligence (AI)

The broad field of building systems that perform tasks requiring pattern recognition, reasoning, language, or decision-making.

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Attention Mechanism

A model component that dynamically focuses on relevant parts of an input when producing an output.

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Autonomous System

A system that can make decisions and act with limited or no direct human control in real time.

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Backpropagation

The core training algorithm that updates model weights by propagating prediction errors backward through the network.

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Baseline Model

A simple reference model used to compare whether more complex approaches actually improve results.

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Benchmark

A standardized test or dataset used to measure and compare model performance.

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Bias

A consistent pattern of error or unfairness in data or model behavior.

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Big Data

Very large and complex datasets that require scalable storage and processing techniques.

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Black-Box Model

A model whose internal reasoning is difficult to interpret directly by humans.

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Calibration

How well a model's confidence scores match actual correctness probabilities.

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Chain-of-Thought

A reasoning style where an AI model decomposes a problem into intermediate steps.

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Classification

A task where a model assigns an input to one or more predefined categories.

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Classifier

A model designed specifically for classification tasks.

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CLIP

A multimodal model architecture that learns shared representations between text and images.

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Compute

The processing resources required to train and run models, often measured in FLOPS or GPU hours.

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Computer Vision

The branch of AI that extracts meaning from images and video.

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Context Window

The maximum amount of input tokens a language model can process at once.

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Continual Learning

Training approaches that let a model keep learning from new data without forgetting prior knowledge.

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Convolutional Neural Network (CNN)

A neural architecture optimized for processing grid-like data such as images.

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Cross-Entropy Loss

A common objective function used to train classification models by penalizing incorrect probabilities.

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Data Augmentation

Techniques that create modified training examples to improve model generalization.

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Data Drift

A shift in real-world input data over time that can degrade model performance.

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Data Labeling

The process of assigning tags or target outputs to raw data for supervised learning.

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Dataset

A collection of structured or unstructured examples used for training, validation, or testing.

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Decision Boundary

The surface in feature space that separates classes predicted by a classifier.

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Decision Tree

A model that makes predictions through a sequence of if-then feature splits.

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Deep Learning

A subset of machine learning that uses many-layer neural networks for representation learning.

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Diffusion Model

A generative architecture that learns to reverse noise to synthesize images, audio, or other content.

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Distillation

Compressing knowledge from a large teacher model into a smaller student model.

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Domain Adaptation

Methods that transfer a model trained in one domain to perform better in another domain.

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Embedding

A numeric vector representation that captures semantic meaning of text, images, or other data.

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Encoder

The component of a model that transforms input into latent representations.

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Ensemble

Combining predictions from multiple models to improve robustness or accuracy.

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Evaluation Set

A held-out dataset used to measure model quality after training.

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Explainability

The degree to which a model's behavior can be interpreted and explained to humans.

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False Negative

An incorrect prediction where a model misses a true positive case.

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False Positive

An incorrect prediction where a model incorrectly flags a negative case as positive.

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Feature

An input variable used by a model to make predictions.

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Feature Engineering

Designing or transforming input variables to make learning easier and more effective.

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Feature Extraction

Converting raw data into informative features that a model can use.

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Few-Shot Learning

Learning or adapting behavior from only a small number of examples.

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Fine-Tuning

Continuing training on domain-specific data to adapt a pre-trained model to a specific task.

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Foundation Model

A large pre-trained model that can be adapted to many downstream tasks.

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Function Calling

A model capability to generate structured calls that trigger external tools or APIs.

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GAN (Generative Adversarial Network)

A generative setup where a generator and discriminator train against each other.

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Generalization

How well a model performs on new, unseen data outside the training set.

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Generative AI

AI systems that produce new content such as text, images, audio, video, or code.

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Gradient

A vector showing how much each parameter should change to reduce loss.

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Gradient Descent

An optimization method that updates parameters in the direction that reduces error.

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Ground Truth

Trusted reference labels used to train or evaluate model outputs.

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Guardrails

Rules, checks, and controls that limit unsafe or undesired model behavior.

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Hallucination

When a model generates fluent but false or unsupported information.

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Human-in-the-Loop

A workflow where humans review, guide, or override AI outputs.

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Hyperparameter

A configuration value set before training, such as learning rate, batch size, or depth.

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In-Context Learning

A model's ability to follow patterns from examples provided directly in the prompt.

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Inference

The runtime phase where a trained model generates predictions or outputs.

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Inference-Time Compute

The amount of processing power consumed while producing each response.

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Instruction Tuning

Fine-tuning a model on instruction-response pairs to improve task following.

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Intent Classification

Predicting the user's purpose from a text query to route it correctly.

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Jailbreak

A prompt technique intended to bypass a model's safety constraints.

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Knowledge Cutoff

The latest point in time reflected in a model's training data.

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Knowledge Distillation

Training a smaller model to imitate the outputs of a larger model.

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Knowledge Graph

A graph structure of entities and relationships used for reasoning or retrieval.

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Label Smoothing

A regularization method that softens hard labels to improve generalization.

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Latency

The time between sending a request and receiving the model's output.

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Large Language Model (LLM)

A language model trained on massive text corpora to generate and analyze text.

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Learning Rate

A training hyperparameter controlling how much parameters change each update step.

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LoRA (Low-Rank Adaptation)

A parameter-efficient fine-tuning method that adds low-rank adapter matrices.

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Loss Function

A mathematical objective that quantifies prediction error during training.

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Machine Learning (ML)

Methods that allow systems to learn patterns from data and improve over time.

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Memory (Agent Memory)

Stored context an AI agent uses across steps or sessions to improve continuity.

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Mixture of Experts (MoE)

An architecture with specialized subnetworks where only selected experts run per input.

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Model Card

Documentation describing a model's intended use, metrics, limitations, and risks.

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Model Drift

Performance degradation over time as real-world conditions diverge from training assumptions.

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Model Quantization

Reducing numeric precision of model weights to decrease memory and inference cost.

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Multimodal Model

A model that can process or generate multiple data types such as text, image, and audio.

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Named Entity Recognition (NER)

An NLP task that identifies entities such as people, places, dates, or organizations.

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Natural Language Processing (NLP)

The branch of AI focused on understanding and generating human language.

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Neural Network

A layered computational model inspired by biological neurons and synapses.

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Normalization

Transforming values to a consistent scale to improve optimization stability.

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OCR (Optical Character Recognition)

Technology that converts text in images or scans into machine-readable text.

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Open-Source Model

A model released with public weights or code for inspection, adaptation, and reuse.

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Overfitting

When a model memorizes training data and performs poorly on unseen inputs.

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Parameter

A learned weight inside a model that influences its outputs.

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Parameter-Efficient Fine-Tuning (PEFT)

Methods that adapt models by training a small subset of added parameters.

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Perplexity

A language-model metric measuring how surprised the model is by true next tokens.

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Pipeline

An ordered workflow of preprocessing, model steps, and postprocessing stages.

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Precision

The proportion of predicted positives that are actually correct.

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Pretraining

Initial large-scale model training on broad data before downstream adaptation.

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Prompt

The input instructions and context provided to a generative model.

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Prompt Engineering

Designing prompts to improve output quality, reliability, and controllability.

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Prompt Injection

An attack pattern where malicious instructions are inserted into model inputs or retrieved content.

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Pruning

Removing less important model weights or neurons to reduce size and compute.

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Quantization

Converting model weights to lower precision formats such as 8-bit or 4-bit.

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RAG (Retrieval-Augmented Generation)

A method that retrieves external knowledge and feeds it into generation at inference time.

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Recall

The proportion of actual positives that a model correctly identifies.

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Recommendation System

A model pipeline that predicts user preferences for ranking content or products.

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Red Teaming

Stress-testing an AI system with adversarial prompts to reveal failures and risks.

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Reinforcement Learning

Training by reward signals where an agent learns actions that maximize long-term return.

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Reinforcement Learning from Human Feedback (RLHF)

A training method that uses human preference signals to shape model behavior.

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Retrieval

Finding relevant documents or records from a knowledge source for a query.

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Reward Model

A model that scores outputs based on preference signals, often used in RLHF pipelines.

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Robustness

A model's ability to maintain performance under noise, shifts, or adversarial inputs.

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Safety Filter

A moderation layer that blocks or rewrites unsafe model inputs or outputs.

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Scaling Law

An empirical relationship showing how performance improves with model size, data, or compute.

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Semantic Search

Search that matches meaning rather than exact keyword overlap, often using embeddings.

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Self-Supervised Learning

Learning representations from unlabeled data by predicting masked or transformed parts.

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Sentiment Analysis

An NLP task that classifies emotional tone or opinion in text.

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Small Language Model (SLM)

A compact language model optimized for lower latency, cost, or on-device usage.

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Sparse Model

A model where many parameters are zero or inactive to reduce computation.

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Supervised Learning

Training a model with labeled examples that map inputs to known outputs.

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Synthetic Data

Artificially generated data used to augment, simulate, or protect sensitive training data.

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System Prompt

A high-priority instruction that sets behavior, policy, and response style for a model.

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Temperature

A sampling setting controlling randomness in generated outputs.

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Token

A chunk of text processed by language models, such as a word piece or symbol.

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Tokenization

The process of splitting text into tokens for model input.

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Tool Use

A model's ability to call external tools such as search, calculators, or APIs.

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Top-k Sampling

A decoding strategy that samples only from the k most likely next tokens.

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Top-p (Nucleus) Sampling

A decoding strategy that samples from the smallest token set whose probabilities sum to p.

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Transfer Learning

Applying knowledge learned in one task or domain to improve another task.

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Transformer

A neural architecture that uses attention to model relationships across sequences in parallel.

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Training Loss

The model error value computed during training and optimized downward over time.

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Unsupervised Learning

Learning patterns from unlabeled data without explicit target outputs.

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Validation Set

A dataset used during development to tune models and prevent overfitting.

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Vector Database

A database optimized for storing and querying high-dimensional embedding vectors.

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Vision-Language Model (VLM)

A multimodal model that jointly processes visual and textual information.

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Weak Supervision

Using noisy, heuristic, or partial labels to train models when clean labels are scarce.

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Weight

A learned numeric value that scales signals passing through a neural network.

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Word Embedding

A dense vector representation of words capturing semantic relationships.

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XAI (Explainable AI)

Techniques and practices for making AI predictions more transparent and understandable.

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Zero-Shot Learning

Solving tasks without task-specific examples by relying on prior general knowledge.

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Agentic Workflow

A multi-step process where an AI system plans, executes, checks results, and iterates toward a goal.

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AI Act

The European Union's risk-based regulatory framework for AI systems and providers.

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Alignment Tax

The extra cost in time, compute, or product velocity required to make systems safer and more controllable.

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Benchmark Leakage

When benchmark test examples or close variants are present in training data, inflating reported performance.

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Causal Inference

Methods for estimating cause-and-effect relationships rather than simple correlations.

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Confidence Interval

A statistical range that likely contains the true value of a measured model metric.

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Constitutional AI

A training and behavior-shaping approach where model outputs are guided by a fixed set of written principles.

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Data Lineage

A record of where data came from, how it was transformed, and where it is used.

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Data Provenance

The documented origin, ownership, and history of a dataset or model artifact.

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Differential Privacy

A privacy technique that adds statistical noise so individual records cannot be reliably inferred from outputs.

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Distilled Model

A smaller model trained to imitate a larger model's behavior while using less compute at inference.

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Embedding Model

A model specialized for converting data into vectors used for semantic search, clustering, and retrieval.

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Eval Harness

A repeatable evaluation framework that runs prompts, datasets, and scoring logic across model versions.

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Feature Store

A managed system for storing and serving validated ML features consistently for training and inference.

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Groundedness

The degree to which an AI response is supported by source data or retrieved evidence.

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Guarded Decoding

A generation strategy that constrains output tokens to valid structures or policy-compliant choices.

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Human Preference Model

A model trained on human rankings to predict which responses users are likely to prefer.

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Inference Endpoint

A deployed API interface that receives model requests and returns predictions in production.

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Knowledge Base

A curated collection of documents or records used for retrieval, support automation, or grounding responses.

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Latent Space

A compressed representational space where similar concepts are positioned near each other as vectors.

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Model Registry

A central catalog for versioning, approving, and tracking models across environments.

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On-Device AI

AI inference performed locally on user hardware rather than in a remote cloud service.

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Output Parser

Logic that validates and converts model output into strongly typed, machine-usable structures.

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Prompt Template

A reusable prompt pattern with variables, formatting rules, and task-specific instructions.

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Retrieval Precision

The proportion of retrieved items that are relevant to the user's query.

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Safety Case

A structured argument, supported by evidence, that an AI system is safe for a defined context of use.

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Shadow Deployment

Running a model in parallel with production traffic without affecting user-facing decisions.

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Structured Output

Model output constrained to a defined schema such as JSON, tool arguments, or typed fields.

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Test-Time Compute

Additional inference computation used during response generation to improve quality or reasoning.

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Trust Calibration

Aligning user confidence in AI outputs with the system's actual reliability in each task.

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Usage-Based Billing

Pricing where costs scale with API calls, tokens, inference time, or consumed compute.

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Zero Data Retention

A policy where request/response payloads are not stored after processing beyond short-lived operational windows.

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