calling card

noun6

1. •
   A small printed card which identifies the bearer, traditionally presented for introduction when making a social visit to a home or when attending a formal social event or business meeting.
2. •
   (figurative) An attribute, symptom, object, or behavior which is distinctly characteristic of someone or something.

   • Free and slightly funky chamber music is the calling card of this festival. — 2006
3. •
   A phonecard.

   • Many experts now advise consumers to use a prepaid calling card to save money on long distance calls while staying in a hotel. — 2003
4. •
   (euphemistic) Excrement, especially of a domestic animal.

   • A guide dog left his calling card on the court at Tuesday night's Magic-Pistons game in Orlando. — 2005
5. •
   A card advertising the services of a prostitute.
6. •
   An explosive dropped from a bomber aeroplane.