signature

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun One's name as written by oneself.
• noun The act of signing one's name.
• noun A distinctive mark, characteristic, or sound indicating identity.
• noun Medicine The part of a physician's prescription containing directions to the patient.
• noun A sign used to indicate key.
• noun A sign used to indicate tempo.
• noun A letter, number, or symbol placed at the bottom of the first page on each sheet of printed pages of a book as a guide to the proper sequence of the sheets in binding.
• noun A large sheet printed with four or a multiple of four pages that when folded becomes a section of the book.

from The Century Dictionary.

• noun A distinguishing sign, mark, or manifestation; an indicative appearance or characteristic, either physical or mental; a condition or quality significant of something: as, the signatures of a person's temperament seen in his face.
• noun Specifically An external natural marking upon, or a symbolical appearance or characteristic of, a plant, mineral, or other object or substance, formerly supposed by the Paracelsians (and still by some ignorant persons) to indicate its special medicinal quality or appropriate use.
• noun The name of a person, or something used as representing his name, affixed or appended to a writing or the like, either by himself or by deputy, as a verification, authentication, or assent (as to a petition or a pledge).
• noun In Scots law, a writing formerly prepared and presented by a writer to the signet to the baron of exchequer, as the ground of a royal grant to the person in whose name it was presented.
• noun A letter or figure placed by the printer at the foot of the first page of every section or gathering of a book.
• noun Hence A sheet; especially, in bookbinders' use, a sheet after it has been folded and is ready to be gathered.
• noun In musical notation, the signs placed at the beginning of a staff to indicate the key (tonality) and the rhythm of a piece.
• noun In entomology, a mark resembling a letter; one of the marks of a signate surface.
• To mark out; distinguish.

from the GNU version of the Collaborative International Dictionary of English.

• noun A sign, stamp, or mark impressed, as by a seal.
• noun Especially, the name of any person, written with his own hand, employed to signify that the writing which precedes accords with his wishes or intentions; a sign manual; an autograph.
• noun (Physiol.) An outward mark by which internal characteristics were supposed to be indicated.
• noun (Old Med.) A resemblance between the external characters of a disease and those of some physical agent, for instance, that existing between the red skin of scarlet fever and a red cloth; -- supposed to indicate this agent in the treatment of the disease.
• noun (Mus.) The designation of the key (when not C major, or its relative, A minor) by means of one or more sharps or flats at the beginning of the staff, immediately after the clef, affecting all notes of the same letter throughout the piece or movement. Each minor key has the same signature as its relative major.
• noun A letter or figure placed at the bottom of the first page of each sheet of a book or pamphlet, as a direction to the binder in arranging and folding the sheets.
• noun The printed sheet so marked, or the form from which it is printed.
• noun (Pharm.) That part of a prescription which contains the directions to the patient. It is usually prefaced by S or Sig. (an abbreviation for the Latin signa, imperative of signare to sign or mark).
• transitive verb To mark with, or as with, a signature or signatures.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A person’s autograph name.
• noun The act of signing one's name.
• noun medicine That part of a doctor’s prescription containing directions for the patient.
• noun music Signs on the stave indicating key and tempo
• noun printing A group of four (or a multiple of four) pages printed such that, when folded, become a section of a book
• noun computing A pattern used for matching the identity of a virus, the parameter types of a method, etc.
• noun cryptography Data attached to a message that guarantees that the message originated from its claimed source.
• noun figurative A mark or sign of implication.
• adjective distinctive, characteristic indicative of identity

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun the sharps or flats that follow the clef and indicate the key
• noun a sheet with several pages printed on it; it folds to page size and is bound with other signatures to form a book
• noun a melody used to identify a performer or a dance band or radio/tv program
• noun your name written in your own handwriting
• noun a distinguishing style