REFERENCE
AI glossary
Plain-language definitions of the terms you will meet in papers, model releases and our courses.
45 terms
- AgentAgents
- A system in which a model repeatedly chooses actions, observes the results and continues toward a goal.Go deeper: Agent
- AlignmentSafety
- Making an AI system pursue the goals and values its designers and users actually intend.Go deeper: Alignment
- BenchmarkEvaluation
- A fixed test set used to compare models. Useful for trends, weak evidence for your specific task.Go deeper: Benchmark
- Chain-of-thoughtTraining
- Having a model write intermediate reasoning steps before its answer, which often improves multi-step problems.Go deeper: Chain-of-thought
- ChunkingBuilding
- Splitting documents into passages before embedding them. Chunk size strongly affects retrieval quality.Go deeper: Chunking
- Constitutional AISafety
- Training a model to critique and revise its own outputs against a written set of principles.Go deeper: Constitutional AI
- ContaminationEvaluation
- When test questions leaked into training data, inflating scores without real capability.Go deeper: Contamination
- Context windowFoundations
- The maximum number of tokens a model can consider at once, including the prompt and its own output.Go deeper: Context window
- DistillationTraining
- Training a smaller model to imitate a larger one, keeping much of its quality at lower cost.Go deeper: Distillation
- DPOTraining
- Direct preference optimisation: learning from preference pairs directly, without a separate reward model.Go deeper: DPO
- EmbeddingFoundations
- A list of numbers that represents the meaning of text, an image or other data, so that similar items sit close together.Go deeper: Embedding
- Eval setEvaluation
- Your own collection of inputs and expected behaviours, used to measure an application and catch regressions.Go deeper: Eval set
- Few-shot promptingBuilding
- Including a handful of worked examples in the prompt to show the model the pattern you want.Go deeper: Few-shot prompting
- Fine-tuningTraining
- Further training of a pre-trained model on a narrower dataset to change its behaviour or specialise it.Go deeper: Fine-tuning
- HallucinationFoundations
- Fluent output that is false or unsupported. It is a natural consequence of predicting likely text, not a rare bug.
- Human-in-the-loopAgents
- Requiring a person to approve or correct certain actions before an AI system carries them out.Go deeper: Human-in-the-loop
- Instruction tuningTraining
- Fine-tuning on instruction–response pairs so a model follows requests rather than just continuing text.Go deeper: Instruction tuning
- JailbreakSafety
- A prompt crafted to make a model ignore its safety rules.Go deeper: Jailbreak
- LLM-as-judgeEvaluation
- Using a model to grade outputs. Scalable, but it has biases toward length, position and its own style.Go deeper: LLM-as-judge
- LoRATraining
- Low-rank adaptation: fine-tuning small added matrices instead of all weights, making customisation cheap.Go deeper: LoRA
- MCPAgents
- Model Context Protocol: an open standard for connecting AI applications to tools and data through servers.Go deeper: MCP
- Mixture of expertsFoundations
- An architecture that routes each token to a few specialised sub-networks, so only part of the model runs per token.
- Model cardSafety
- A document describing a model’s intended use, training data, evaluations and known limitations.
- ParametersFoundations
- The learned numbers inside a model. More parameters often, but not always, means more capability.Go deeper: Parameters
- Pre-trainingTraining
- The first, largest training stage, in which a model learns to predict text from a broad corpus.Go deeper: Pre-training
- PromptBuilding
- The input given to a model: instructions, context, examples and the question itself.Go deeper: Prompt
- Prompt cachingBuilding
- Reusing the processed form of a repeated prompt prefix to cut latency and cost.
- Prompt injectionSafety
- Malicious instructions hidden in content a model reads, such as a web page or document, that try to hijack its behaviour.Go deeper: Prompt injection
- QuantisationTraining
- Storing weights at lower numeric precision to cut memory and speed up inference, usually with a small quality loss.
- RAGBuilding
- Retrieval-augmented generation: fetching relevant documents and placing them in the prompt so answers are grounded in them.Go deeper: RAG
- ReActAgents
- A pattern that interleaves reasoning steps with actions and observations in one loop.Go deeper: ReAct
- Red-teamingEvaluation
- Deliberately probing a system for harmful, unsafe or broken behaviour before others find it.Go deeper: Red-teaming
- RerankingBuilding
- A second pass that re-scores retrieved passages with a more accurate model before they reach the prompt.Go deeper: Reranking
- RLHFTraining
- Reinforcement learning from human feedback: training a reward model on human preferences, then optimising the model against it.Go deeper: RLHF
- Scaling lawsFoundations
- Empirical relationships between model size, data, compute and performance, used to plan training runs.Go deeper: Scaling laws
- Self-attentionFoundations
- A mechanism that lets each token weigh every other token in the input when building its representation.Go deeper: Self-attention
- Structured outputBuilding
- Constraining a model to reply in a fixed format such as JSON that matches a schema.Go deeper: Structured output
- System promptBuilding
- Standing instructions that set a model’s role, rules and format for a whole conversation.Go deeper: System prompt
- TemperatureFoundations
- A sampling setting that controls randomness. Lower values give more predictable output, higher values more varied output.
- Test-time computeTraining
- Spending extra computation while answering, for example longer reasoning or multiple samples, to improve results.Go deeper: Test-time compute
- TokenFoundations
- The unit of text a model reads and writes, often a word piece. Pricing, speed and context limits are all counted in tokens.Go deeper: Token
- Tool callingAgents
- A model emitting a structured request to run a function, such as a search or a calculator, whose result is fed back to it.Go deeper: Tool calling
- TransformerFoundations
- The neural network architecture behind modern language models, built around self-attention.Go deeper: Transformer
- Vector databaseBuilding
- A store that indexes embeddings for fast similarity search, commonly used for retrieval.Go deeper: Vector database
- Vision-language modelBuilding
- A model that takes images and text together, for example to read a chart or describe a photo.Go deeper: Vision-language model