K-T-B (Hebrew: כ-ת-ב; Arabic: ك-ت-ب) is a triconsonantal root of a number of Semitic words, typically those having to do with writing.
The words for "office", "writer" and "record" all reflect this root. Most notably, the Arabic word kitab ("book") is also used in a number of Semitic and Indo-Iranian languages, as well as Turkish. One cultural example would be the Mishnaic expression Katuv or the cognate Arabic expression transliterated as Maktoub, which may be translated as "it is written". Another would be the Koutoubia mosque of Marrakech, whose name is taken from the librarians and booksellers who once occupied that area.[citation needed]