← LEARN AI
REFERENCE

AI Glossary

53 terms defined in plain language. No jargon without explanation.

53 terms
A

Agentic AI

AI Agents & Tools

AI systems designed to operate with autonomy — planning multi-step workflows, making decisions, and executing actions without human approval at each step. The next evolution beyond chatbots.

AI Agent

AI Agents & Tools

An AI system that can autonomously perform multi-step tasks — browsing the web, writing and running code, using software tools, making decisions — with minimal human oversight. The current frontier of AI deployment in 2025-2026.

AI Governance

Regulation & Policy

The frameworks, policies, and institutions for overseeing AI development and deployment. Includes government regulation, industry self-regulation, international agreements, and technical standards.

AI Safety

Safety & Ethics

The field focused on ensuring AI systems behave as intended and don't cause unintended harm. Covers everything from preventing biased outputs to theoretical work on aligning superintelligent systems.

Alignment

Safety & Ethics

The challenge of ensuring AI systems pursue goals that are beneficial to humans. A misaligned superintelligent AI wouldn't necessarily be malicious — it might simply optimize for the wrong objective with devastating efficiency.

API (Application Programming Interface)

Industry & Business

How software systems talk to each other. In AI context, the API is how developers access AI models — sending text in, getting responses back. OpenAI, Anthropic, and Google all offer APIs to their models.

Artificial General Intelligence (AGI)

Core Concepts

A hypothetical AI system that can understand, learn, and apply knowledge across any intellectual task a human can do — not just narrow, specific ones. No AGI system exists yet. Timelines for when (or whether) it will are hotly debated.

Artificial Intelligence (AI)

Core Concepts

A broad field of computer science focused on building systems that can perform tasks typically requiring human intelligence — reasoning, learning, perception, language understanding, and decision-making.

Attention Mechanism

Models & Architecture

The core innovation of Transformers. Instead of processing text sequentially (word by word), attention lets the model look at all words simultaneously and decide which ones are most relevant to each other. This is why LLMs can understand context across long passages.

B

Backpropagation

Training & Techniques

The fundamental algorithm for training neural networks. It calculates how much each parameter contributed to an error, then adjusts the parameters to reduce that error. Popularized by Hinton, Rumelhart, and Williams in 1986 — the paper that made deep learning possible.

Benchmark

Measurement & Evaluation

A standardized test for measuring AI performance. Examples: MMLU (general knowledge), HumanEval (coding), GSM8K (math). Useful but imperfect — models can be optimized for benchmarks without gaining real capability.

Brier Score

Measurement & Evaluation

A metric for evaluating probabilistic forecasts. Measures the mean squared error between predicted probabilities and actual outcomes. Score of 0 = perfect accuracy, 0.25 = coin-flip useless. TexTak uses Brier scores to track forecast accuracy.

C

Compute

Industry & Business

The computational resources required to train and run AI models. Measured in GPU-hours or FLOPS. Access to compute is one of the primary barriers to entry in frontier AI development — training a single large model can cost tens of millions of dollars.

Computer Vision

Core Concepts

AI that processes and understands visual information — images and video. Applications include facial recognition, medical image analysis, autonomous driving, and image generation.

Constitutional AI

Training & Techniques

Anthropic's approach to AI alignment where the model is trained against a set of principles (a 'constitution') rather than relying solely on human feedback. The model critiques and revises its own outputs based on these principles.

Context Window

Models & Architecture

The maximum amount of text a language model can consider at once. Measured in tokens. A 128K context window means the model can 'see' roughly 100,000 words at a time. Larger windows enable longer documents and conversations.

D

Deep Learning

Core Concepts

A subset of machine learning that uses neural networks with many layers (hence 'deep'). The approach that powers most modern AI, including language models, image generators, and speech recognition.

Diffusion Model

Generative AI

The architecture behind DALL-E, Stable Diffusion, and Midjourney. Works by learning to remove noise from images — training on the process of gradually corrupting images with static, then learning to reverse it. Generation starts from pure noise and progressively refines it into a coherent image.

E

EU AI Act

Regulation & Policy

The European Union's comprehensive AI regulation framework, passed in 2024. Classifies AI systems by risk level (unacceptable, high, limited, minimal) and imposes requirements accordingly. The most significant AI regulation in the world to date.

F

Fine-tuning

Training & Techniques

Taking a pre-trained model and training it further on a specific, smaller dataset to specialize it for a particular task. Like a medical school graduate doing a residency in cardiology.

Foundation Model

Models & Architecture

A large AI model trained on broad data that can be adapted to many tasks. Rather than building a separate model for each use case, you start with a foundation model and fine-tune or prompt it. GPT-4, Claude, and LLaMA are foundation models.

Frontier Model

Models & Architecture

The most capable AI models at any given time — the cutting edge. Currently refers to GPT-4-class and above systems from OpenAI, Anthropic, Google, and Meta. The frontier advances every few months.

G

GAN (Generative Adversarial Network)

Generative AI

A model architecture where two neural networks compete: one generates content, the other judges whether it's real or fake. The competition drives both to improve. Invented by Ian Goodfellow in 2014. Preceded the diffusion models that power modern image generators.

Generative AI

Generative AI

AI systems that create new content — text, images, music, video, code — rather than just analyzing or classifying existing content. The category that includes ChatGPT, DALL-E, Midjourney, Stable Diffusion, and Sora.

GPU (Graphics Processing Unit)

Industry & Business

The hardware that powers AI training and inference. Originally designed for video game graphics, GPUs excel at the parallel mathematical operations that neural networks require. NVIDIA dominates the market.

Guardrails

Safety & Ethics

Safety mechanisms built into AI systems to prevent harmful outputs — content filters, refusal behaviors, output classifiers. The boundaries that keep models from generating dangerous, illegal, or harmful content.

H

Hallucination

Generative AI

When an AI model generates information that sounds confident and plausible but is factually wrong. Not lying (the model has no intent) — more like confabulation. A fundamental limitation of current language models that remains unsolved.

I

Inference

Training & Techniques

When a trained model generates output — answering a question, creating an image, making a prediction. Training is learning; inference is using what was learned. Most AI costs are now in inference, not training.

Interpretability / Explainability

Safety & Ethics

The ability to understand why an AI model made a specific decision. Most deep learning models are 'black boxes' — they work, but nobody fully understands how. Interpretability research tries to open the box.

L

Large Language Model (LLM)

Models & Architecture

A neural network trained on massive amounts of text data that can generate, summarize, translate, and reason about language. Examples: GPT-4, Claude, LLaMA, Gemini. 'Large' refers to billions of parameters.

M

Machine Learning (ML)

Core Concepts

A subset of AI where systems learn patterns from data rather than being explicitly programmed with rules. Instead of writing 'if X then Y,' you show the system thousands of examples and it figures out the pattern.

MCP (Model Context Protocol)

AI Agents & Tools

Anthropic's open standard for connecting AI models to external data sources and tools. Allows Claude and other models to interact with services like Google Drive, Slack, and databases through a standardized interface.

Moat

Industry & Business

A competitive advantage that's hard for rivals to replicate. In AI: is it data, compute, talent, distribution, or brand? Whether any AI company has a durable moat — or whether open-source models erode all moats — is an active strategic question.

Multimodal

Models & Architecture

AI systems that can process multiple types of input — text, images, audio, video — rather than just one. GPT-4, Claude, and Gemini are multimodal: you can send them images and they can describe, analyze, or reason about them.

N

Natural Language Processing (NLP)

Core Concepts

The branch of AI focused on enabling computers to understand, interpret, and generate human language. Includes everything from spell-check to chatbots to machine translation.

Neural Network

Core Concepts

A computing system inspired by biological neurons. Layers of interconnected nodes process information, with each connection having a learnable weight. The 'learning' happens by adjusting these weights based on data.

O

Open Weights / Open Source

Models & Architecture

Models whose trained parameters are publicly released, allowing anyone to run, modify, and build on them. Meta's LLaMA and Mistral are open-weight. Distinct from 'open source' in the traditional software sense — training data and methods may not be shared.

P

Parameter

Models & Architecture

A learnable value in a neural network — essentially a number that gets adjusted during training. GPT-4 reportedly has over 1 trillion parameters. More parameters generally (but not always) means more capability.

Perplexity

Measurement & Evaluation

A measurement of how well a language model predicts text. Lower perplexity = better prediction. Roughly: if the model's perplexity on a sentence is 10, it's as 'surprised' as if it had to choose between 10 equally likely options for each word.

Prompt Engineering

Training & Techniques

The practice of crafting inputs to AI models to get better outputs. Since LLMs are sensitive to how questions are phrased, the wording, structure, and examples in a prompt significantly affect the response quality.

R

RAG (Retrieval-Augmented Generation)

Training & Techniques

A technique that gives language models access to external knowledge by retrieving relevant documents before generating a response. Reduces hallucination by grounding answers in actual sources rather than relying solely on training data.

Red Teaming

Safety & Ethics

Deliberately trying to make AI systems fail, produce harmful content, or behave unexpectedly. Named after military exercises. AI companies employ red teams to find vulnerabilities before deployment.

Responsible AI

Regulation & Policy

An umbrella term for practices aimed at developing AI that is fair, transparent, accountable, and safe. Every major AI company has a responsible AI team. Critics argue the term is often more marketing than substance.

RLHF (Reinforcement Learning from Human Feedback)

Training & Techniques

A training technique where human evaluators rank model outputs by quality, and the model learns to produce responses that humans prefer. The key method behind making raw language models into helpful assistants like ChatGPT and Claude.

S

Scaling Laws

Industry & Business

The empirical observation that model performance improves predictably as you increase model size, dataset size, and compute. The intellectual foundation behind the 'bigger is better' approach to AI development. Whether scaling laws will continue to hold is a central debate.

Synthetic Data

Training & Techniques

Training data generated by AI models rather than collected from the real world. Used when real data is scarce, expensive, or privacy-sensitive. Increasingly used to train newer models — raising questions about 'model collapse' when AI trains on AI output.

T

Text-to-Image

Generative AI

AI systems that generate images from written descriptions. Type 'a cat wearing a space suit on Mars' and get an image. Powered by diffusion models or transformer-based architectures.

Text-to-Video

Generative AI

AI systems that generate video clips from written descriptions. OpenAI's Sora is the most prominent example. Still early — physics and consistency are imperfect — but advancing rapidly.

Token

Models & Architecture

The basic unit that language models process. Not exactly a word — more like a word fragment. 'Understanding' might be split into 'under' + 'standing.' A typical English word is 1-3 tokens. Context windows are measured in tokens.

Tool Use

AI Agents & Tools

The ability of AI models to interact with external tools — search engines, calculators, code interpreters, APIs, databases. Extends LLMs beyond text generation into real-world action.

Training

Training & Techniques

The process of feeding data to a neural network so it can learn patterns. Like education for AI — the model sees billions of examples and adjusts its parameters to get better at predicting what comes next.

Transformer

Models & Architecture

The neural network architecture behind virtually every modern LLM. Introduced in the 2017 paper 'Attention Is All You Need.' Its key innovation — the attention mechanism — allows the model to weigh the relevance of different parts of the input when generating each piece of output.

Turing Test

Measurement & Evaluation

Alan Turing's proposed measure of machine intelligence: if a human can't distinguish between a machine's responses and a human's in conversation, the machine exhibits intelligent behavior. Modern AI arguably passes narrow versions but the deeper question remains debated.