calling card vs sig

calling card

noun
  • 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. 

  • A card advertising the services of a prostitute. 

  • Excrement, especially of a domestic animal. 

  • An attribute, symptom, object, or behavior which is distinctly characteristic of someone or something. 

  • A phonecard. 

sig

noun
  • A signature, especially on emails or newsgroup postings. 

How often have the words calling card and sig occurred in a corpus of books? (source: Google Ngram Viewer )