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