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Common AI Terms: A Glossary

Short, plain-English definitions of forty terms you will meet when working with AI and machine learning.

Editorial team 2 min read

A quick reference to the vocabulary used across AI projects.

Core Concepts

  • Algorithm — a procedure for learning from data, such as gradient boosting.
  • Model — the trained result that makes predictions.
  • Parameters / weights — numbers learned during training.
  • Hyperparameters — settings chosen before training.
  • Training / inference — learning from data / using the model on new inputs.
  • Features / labels — model inputs / the answers it learns to predict.

Evaluation

  • Accuracy — share of correct predictions.
  • Precision / recall — of positive predictions, how many were right / of actual positives, how many were found.
  • Overfitting — memorising training data instead of learning the pattern.
  • Baseline — a simple reference result every model must beat.
  • Benchmark — a standard test used to compare models.

Deep Learning

  • Neural network — layers of connected units that learn representations.
  • Transformer — the architecture behind modern language models, built on attention.
  • Embedding — a vector of numbers representing meaning.
  • Fine-tuning — further training a pretrained model on specific data.
  • Transfer learning — reusing knowledge from one task for another.

Language Models

  • LLM — large language model.
  • Token — a chunk of text the model processes.
  • Context window — the maximum tokens per request.
  • Prompt — the input given to a model.
  • Hallucination — confident but false output.
  • RAG — retrieval-augmented generation: grounding answers in retrieved documents.
  • Agent — an LLM that uses tools in a loop to complete tasks.

Responsible AI

  • Bias — systematic unfairness in data or outputs.
  • Explainability — understanding why a model made a prediction.
  • Model card — documentation of a model's use, data and limitations.
  • Drift — degradation as real-world data changes.

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