dating vs double date

dating

noun
  • A form of romantic courtship typically between two individuals with the aim of assessing the other's suitability as a partner in an intimate relationship or as a spouse. 

  • An estimation of the age of an artifact, biological vestige, linguistic usage, etc. 

  • The setting of a date on which an event or transaction is to take place or take effect. 

double date

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

verb
  • To go on a double date. 

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