calling card is a noun meaning "a card that is used instead of cash to make telephone calls". It carries 3 recorded senses.
a card that is used instead of cash to make telephone calls
a printed or written greeting that is left to indicate that you have visited
a distinguishing characteristic or behavior
“bombs are a terrorist's calling cards”
Definitions, synonyms and semantic relations for calling card come from Princeton University’s WordNet. Commonness is measured against a corpus of everyday English. Full sources and licences.