Definition of: signature

(sig′nə·chər) noun
1. The name of a person, or something representing his name, written, stamped, or inscribed by himself or by deputy, as a sign of agreement or acknowledgment.
2. Printing a A distinguishing mark, letter, or number on the first page of each form or sheet of a book, as a guide to the binder. b The form or sheet on which this mark is placed. c One of the fractional parts of a book; a folded printed sheet, usually comprising 16 pages.
3. Music A symbol or group of symbols at the beginning of a staff, indicating time or key. See KEY SIGNATURE, TIME SIGNATURE.
4. In radio, the musical number or sound effect that introduces or closes a given program.
5. Zool. A color mark resembling a letter.
6. Med. The part of a physician's or pharmacist's prescription that indicates how the medicine is to be taken: usually preceded by S. or Sig. [<F <Med. L signatura <L signatus. See SIGNATORY.]