calling card

Short definition from Wiktionary

Noun

1. 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. 2
   An attribute, symptom, object, or behavior which is distinctly characteristic of someone or something.
3. 3
   Excrement, especially of a domestic animal.
4. 4
   A phonecard.
5. 5
   A card advertising the services of a prostitute.
6. 6
   An explosive dropped from a bomber aeroplane.
7. 7
   Alternative spelling of calling card.