query
Like asking a librarian for a specific book, it is a structured question you send to a database to get back matching data.
Imagine filling out a slip that says which author and which title you want. A query is the precise request you send to a database so it can find, add, change, or remove records.
This matters because apps need exact slices of data: the latest messages, one user’s orders, or totals for a chart. Vague questions waste time and cost money.
In practice you write SQL, which is a language for databases, or you call a helper function in a client library, which is code that talks to a service for you, to select rows, filter by conditions, sort, and limit how many come back.