NLU
Natural Language Understanding
In one line
NLU (Natural Language Understanding) is the field focused on machines interpreting human language intent and context — the foundation under intent analysis and query handling in AI search.
Going deeper
NLU is the slice of natural language processing focused on extracting meaning, intent and context from input — intent classification, entity recognition, relation extraction, disambiguation. The query rewriting and query decomposition steps inside AI search sit on top of NLU.
Knowing the term helps marketers see why AI search 'matches on intent, not keywords' is more than a slogan. The phenomenon where many different phrasings of the same intent converge on the same answer and the same cited sources is, mechanically, NLU doing its job.
The content implication is to plan pages around intent rather than around one or two keyword phrasings. A page that naturally covers several wordings of the same underlying intent matches more reliably at the NLU stage than a page tuned to a narrow exact-match string.
Related terms
Query Rewriting
Query rewriting is the step where the search system rephrases a user's prompt into a form better suited for retrieval — typically the first stage of an AI search pipeline.
GEO·AEOQuery Decomposition
Query decomposition is the technique of breaking a complex question into smaller, easier sub-questions — a building block used widely across AI search and LLM reasoning.
LLMEmbedding
An embedding is a numeric vector representation of text or other data that preserves semantic meaning — the foundation of semantic search, vector databases and RAG.
LLMRAG
RAG (Retrieval-Augmented Generation) lets an LLM fetch external documents at answer time and ground its response in them — the technique behind ChatGPT Search, Perplexity and most AI search products.
GEO·AEOGEO
GEO (Generative Engine Optimization) is the practice of optimizing content and data so that a brand gets cited and recommended inside generative AI search answers like ChatGPT, Perplexity and Google AI Overviews.
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