What is a retrieval query?
The text a search system actually runs against your library. It is rarely the question you typed.
A retrieval query is the text a search system actually runs against your library, and it is rarely the question you typed. The original question is rewritten into forms the indexes match well: keywords for the lexical search, an embedding for the vector search, sometimes several variants to widen the net. What comes back depends on this step as much as on the index; a library can only return what its query could reach.
The question, rewritten for the index.
You ask in sentences; indexes match in their own currencies. Semantic search compares meanings, so the query becomes a vector that stands for what you meant. Keyword search compares terms, so the query becomes the words a relevant document would plausibly contain. Most grounded tools build both from your question and run them together, sometimes adding a variant or two for good measure. The step is invisible when it works, which is exactly why it deserves attention: it sits between your question and everything the answer can draw on.
Why wording matters to a machine.
A human hears "battery life" and "runtime" as the same question. A keyword index does not, and even a meaning-based search can be pulled aside by phrasing that leans toward the wrong sense of a word. This is why query construction is engineering rather than a formality: strip the words that carry no evidence, keep the ones a source would use, and let the two search methods cover each other's misses. A well-built query is one the library could actually answer, which is a different thing from a well-built question.
What a good query earns you.
Retrieval sits at the front of every grounded answer, so its quality caps everything after it. In a retrieval-augmented loop, the model can only cite passages the query surfaced, and the verification pass can only check claims against material that arrived. A poor query quietly produces confident answers built on the wrong passages, which is the hardest failure to notice from the outside. Tools that show their work let you see what was retrieved; that visibility is how a wrong query gets caught before it becomes a wrong answer.