double date vs gathering

double date

noun
  • A (romantic) date that two couples go on together. 

verb
  • To go on a double date. 

gathering

noun
  • A meeting or get-together; a party or social function. 

  • A group of people or things. 

  • A section, a group of bifolios, or sheets of paper, stacked together and folded in half. 

  • The collection of produce, items, goods, etc.; the practice of collecting food from nature. 

  • A tumor or boil suppurated or maturated; an abscess. 

  • A charitable contribution; a collection. 

adj
  • That gathers together. 

How often have the words double date and gathering occurred in a corpus of books? (source: Google Ngram Viewer )