Glossary

Plain-language definitions of AI terms. Tap a letter to jump, or scroll the full table.

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TermDefinition
Activation Function

A nonlinear function applied to a neuron's weighted sum that lets neural networks learn complex patterns. Common examples include ReLU, sigmoid, and tanh.

Adversarial Attacks

Deliberate, often small, perturbations to input data designed to fool a machine-learning model into making incorrect predictions. They expose vulnerabilities in models and are a key concern for AI robustness and security.

Affine Functions

Functions of the form f(x) = Wx + b that combine a linear transformation with a translation. They are the mathematical building blocks of linear layers in neural networks.

Agent

An AI system that can perceive its environment, reason, and take actions autonomously to achieve a goal. Modern agents often combine language models with tools and memory.

AI Alignment

The field of ensuring an AI system's goals and behavior reliably match human values and intentions. It is central to building safe and beneficial advanced AI.

AI Safety

The discipline of preventing AI systems from causing harm, whether through accidents, misuse, or unintended behavior. It spans technical robustness, alignment, and governance.

Algorithmic Fairness

The study and practice of designing algorithms that avoid unjust discrimination across groups defined by attributes like race, gender, or age.

Artificial Intelligence (AI)

The field of computer science devoted to building machines that can perform tasks requiring human-like intelligence, such as reasoning, perception, and learning.

Autoencoders

Neural networks that learn to compress input data into a compact representation and reconstruct it, useful for dimensionality reduction, denoising, and anomaly detection.

Backpropagation

The core algorithm for training neural networks that computes gradients of the loss with respect to weights via the chain rule and propagates them backward.

Batch Normalization

A technique that normalizes the inputs of each layer within a mini-batch to stabilize and accelerate neural-network training.

BERT (Bidirectional Encoder Representations from Transformers)

A transformer-based language model that reads text in both directions to build deep contextual word representations, revolutionizing NLP tasks.

Bias Mitigation

Methods applied to data, models, or decisions to reduce unfair bias and improve fairness across demographic groups.

Bias-Variance Tradeoff

The balance between a model's tendency to oversimplify (bias) and its sensitivity to noise in training data (variance); good models minimize total error from both.

BitNet

A family of 1-bit large language models (such as BitNet b1.58) that use ternary or binary weights to drastically cut memory and compute while preserving accuracy.

Chain-of-Thought Prompting

A prompting technique that encourages a model to generate intermediate reasoning steps, improving performance on complex math and logic problems.

Checkpoints

Saved snapshots of a model's weights and training state at a point in time, allowing training to resume or the model to be reused and deployed.

Computational Creativity

The study and development of AI systems that exhibit behavior deemed creative in domains such as art, music, literature, and design.

Compute-Efficient AI

Approaches, such as sparse models and quantization, that achieve strong performance while reducing the computational cost of training and inference.

Contrastive Divergence

An approximation algorithm used to train energy-based models like Restricted Boltzmann Machines by comparing data and generated samples.

Contrastive Learning

A self-supervised method that learns representations by pulling similar examples together and pushing dissimilar ones apart.

Convolutional Neural Networks (CNNs)

Neural networks using convolution operations to efficiently process grid-structured data like images, excelling at vision tasks.

Data Augmentation

Techniques that artificially expand a training set by transforming inputs (e.g., cropping, rotating, or paraphrasing) to improve generalization.

Deep Learning (DL)

A branch of machine learning using multi-layer neural networks to learn hierarchical representations from large amounts of data.

Diffusion Models

Generative models that learn to reverse a gradual noising process, producing high-quality images, audio, and other data from random noise.

Domain Adaptation

A transfer-learning technique that adapts a model trained on one distribution (source) to perform well on a related but different distribution (target).

Edge Devices

Small, often battery-powered computing devices (phones, sensors, IoT hardware) that run AI models locally rather than in the cloud.

Embedding

A list of numbers representing a piece of text's meaning, so similar texts sit close together in vector space.

Embedding Space

The geometric space in which embeddings live, where proximity reflects similarity in meaning or function.

Ethical AI

The practice of designing, deploying, and governing AI in ways that respect human rights, fairness, accountability, and societal well-being.

Explainability

The degree to which a human can understand the reasons a model produced a particular output.

Explainable AI (XAI)

Techniques and tools that make AI decisions transparent and interpretable to users, regulators, and developers.

Feature Engineering

The process of selecting, transforming, or creating input variables to improve a model's predictive performance.

Federated AI

AI systems that coordinate learning across many decentralized devices or organizations while keeping raw data local.

Federated Learning

A training approach where models are updated on-device and only the updates are shared centrally, preserving data privacy.

Feedforward

A network architecture where information flows in one direction from input to output with no cycles or feedback loops.

Few-Shot Learning

A model's ability to learn a new task from only a handful of examples, often by leveraging prior knowledge or in-context examples.

Few-Shot Prompting

Providing a language model with a few illustrative examples inside the prompt so it can infer the desired task without weight updates.

Fine-tuning

Further training a pretrained model on a narrow dataset so it adopts a style or specialty.

Generative Adversarial Networks (GANs)

A framework where a generator and discriminator compete, enabling the synthesis of realistic images, audio, and other data.

Generative AI

AI systems that create new content such as text, images, audio, or video, typically by learning the underlying distribution of training data.

GPT (Generative Pre-trained Transformer)

A family of decoder-only transformer models pre-trained on vast text corpora and fine-tuned for language generation and instruction following.

Gradient Descent

An optimization method that iteratively adjusts parameters in the direction opposite their gradient to minimize a loss function.

Hallucination

Confidently wrong output — the model fills gaps with plausible text instead of saying "I don't know."

Hyperparameter

A configuration setting chosen before training (such as learning rate or batch size) that controls how a model learns.

Knowledge Distillation

Training a smaller "student" model to mimic a larger "teacher" model, transferring capability while reducing size and cost.

Latent Space

The compressed, abstract representation space a model learns, where each point corresponds to a possible input or concept.

LoRA (Low-Rank Adaptation)

A parameter-efficient fine-tuning method that injects small trainable rank-decomposition matrices, avoiding updates to all original weights.

Loss Function

A function that quantifies how far a model's predictions are from the true targets, guiding the learning process.

LSTM (Long Short-Term Memory)

A type of recurrent neural network with gating mechanisms that captures long-range dependencies in sequential data.

Machine Learning (ML)

A subset of AI where systems improve at tasks by learning patterns from data rather than through explicit programming.

Meta-Learning

Learning algorithms that improve their own learning process, sometimes called "learning to learn," across many tasks.

Model

The learned function that turns input (text, image) into output. Training fixes its weights; inference just runs it.

Model Compression

Techniques such as pruning, quantization, and distillation that shrink models for faster, cheaper deployment.

Model Distillation

A form of knowledge distillation in which a compact model is trained to reproduce the behavior of a larger, more capable model.

Multi-Modal AI

AI systems that process and relate information across multiple modalities such as text, images, audio, and video.

Named Entity Recognition (NER)

An NLP task that identifies and classifies entities such as names, organizations, and locations within text.

Natural Language Processing (NLP)

The field of enabling computers to understand, generate, and manipulate human language.

Neural Networks

Computational models inspired by the brain, composed of layers of interconnected nodes that learn mappings from inputs to outputs.

Optimizer

The algorithm (such as Adam or SGD) that updates model weights using gradients to reduce the loss during training.

Overfitting

When a model learns training-data noise rather than the underlying pattern, performing well on training data but poorly on new data.

Perceptron

The simplest type of neural unit that computes a weighted sum and applies a step function, foundational to neural-network theory.

Post-Training Quantization (PTQ)

Converting a trained model's weights to lower-precision formats after training to reduce size and speed up inference.

Precision

A classification metric measuring the share of positive predictions that were actually correct (true positives divided by all positive predictions).

Prompt Engineering

The craft of designing input prompts to reliably steer a language model toward desired outputs.

Prompt Injection

An attack that embeds malicious instructions inside text a model processes, hijacking its behavior or bypassing safeguards.

Prompt Tuning

A parameter-efficient method that prepends trainable soft-prompt vectors to a frozen model instead of retraining its weights.

Pruning

Removing unimportant weights or neurons from a model to make it smaller and faster with minimal accuracy loss.

Quantization

Representing model weights and activations with fewer bits (e.g., 8-bit integers) to reduce memory and computation.

RAG

Retrieval-Augmented Generation: the model fetches relevant documents, then answers from them — reducing hallucination.

RAG (Retrieval-Augmented Generation)

A technique that grounds a language model's answers in retrieved external documents, improving factual accuracy and citation.

Recurrent Neural Networks (RNNs)

Neural networks with loops that maintain a hidden state, suited to sequential data like text and time series.

Regularization

Methods such as dropout and weight decay that constrain a model to reduce overfitting and improve generalization.

Reinforcement Learning (RL)

A learning paradigm where an agent improves by receiving rewards or penalties from interacting with an environment.

RLHF (Reinforcement Learning from Human Feedback)

Fine-tuning models using human preference signals to make their outputs more helpful, harmless, and aligned.

Self-Supervised Learning

Learning from unlabeled data by generating supervisory signals from the data itself, such as predicting masked parts.

Semantic Segmentation

Assigning a class label to every pixel in an image so that objects are understood at the pixel level.

Semi-Supervised Learning

Training with a small amount of labeled data combined with a large amount of unlabeled data to improve performance.

Sparse Modeling

Representing data or models with mostly zero values, improving efficiency and interpretability.

Straight-Through Estimator (STE)

A trick that passes gradients unchanged through non-differentiable operations like rounding, enabling quantization-aware training.

Synthetic Data

Artificially generated data used to train or test models, especially when real data is scarce, sensitive, or costly.

Synthetic Media

Audio, images, video, or text generated or manipulated by AI, including deepfakes and other generative content.

Token

A chunk of text (roughly 4 characters in English) that models read and write. Pricing and context limits are counted in tokens.

Tokenization

Splitting raw text into tokens (words, subwords, or characters) that a model can process numerically.

Training

The process of adjusting a model's parameters using data and an optimization algorithm to minimize a loss function.

Transfer Learning

Reusing a model trained on one task as the starting point for a related task, speeding up and improving learning.

Transformer-Based Models

Models built on the transformer architecture, which uses self-attention to weigh relationships across an entire sequence.

Transformers

A neural architecture introduced in 2017 that relies on self-attention, now the backbone of most modern language and vision models.

Underfitting

When a model is too simple to capture the underlying pattern, performing poorly even on training data.

Unsupervised Learning

Learning from unlabeled data to discover structure, such as clusters or low-dimensional representations.

Vibe Coding

A casual, AI-assisted coding style where a developer describes intent to a language model and accepts its generated code largely by feel, with minimal manual review.

Zero-Shot Learning

A model's ability to perform a task or recognize a class it was never explicitly trained on, using general knowledge and instructions.