signature Definition

signature
noun

1. One's name written by oneself, or a representative symbol, as a formal mark of authorization, etc.

Thesaurus: autograph, endorsement, John Hancock (US slang), John Henry (US slang), inscription, mark, sign, trademark.
2. An indication of key (key signature) or time (time signature) at the beginning of a line of music, or where a change occurs.
3. A large sheet of paper with printed pages on it, each with a numeral or letter at the bottom, which when folded forms a section of a book.
4. A letter or number at the foot of such a sheet, indicating the sequence in which such sheets are to be put together.

Etymology: 16c: from Latin signatura, from signare to sign.