A distinctive mark, characteristic, or sound indicating identity: A surprise ending is the signature of an O. Henry short story.
Medicine The part of a physician's prescription containing directions to the patient.
Music A sign used to indicate key.
Music A sign used to indicate tempo.
Printing 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.
Printing A large sheet printed with four or a multiple of four pages that when folded becomes a section of the book.