Writer's Glossary - Query

Query, Query Letter (N)

(1) a one page letter to an editor pitching a proposed non-fiction article.
(2) a pitch to a director for a screenplay.
(3) a letter to an editor for a novel usually accompanied with a synopsis and sample chapters.

Source: www.writefromhome.com

A query letter "pitches" an article or book idea to an editor to see if that editor might be interested in purchasing the proposed or completed manuscript.

Source: www.thescriptorium.net

An inquiry from a writer to an editor of a magazine, newspaper, etc., regarding the acceptability of or interest in an idea for an article, news story, or the like: usually presented in the form of a letter that outlines or describes the projected piece.

Source: dictionary.reference.com

Query (V)

The act of writing and submitting a query letter.

Source: Brian Westover