What is the meaning of signature?

noun

• Your name written in your own handwriting.
• A distinguishing style.
  • usage: "this room needs a woman's touch"
  • synonyms: touch
• A melody used to identify a performer or a dance band or radio/tv program.
  • synonyms: signature tune, theme song
• The sharps or flats that follow the clef and indicate the key.
  • synonyms: key signature
• A sheet with several pages printed on it; it folds to page size and is bound with other signatures to form a book. .