greeting card vs salutation

greeting card

noun
  • A card, typically folded in half and available commercially, that is sent to someone as a greeting. (This entry is a translation hub.) 

salutation

noun
  • A greeting, salute, or address; a hello. 

  • The act of greeting. 

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