first base vs number one

first base

noun
  • The base after home plate in a counter-clockwise path around a baseball infield. 

  • Completion of the first phase of an activity. 

  • Kissing, regarded as the first phase of a sexual relationship. 

  • The betting spot located immediately to the left of the dealer, which is first to receive cards and first to act. 

number one

noun
  • The batsman who opens the batting. 

  • The main goalkeeper of a team, so-called because they wear the number 1 on the back of their kit. 

  • The most important person, the one who is in charge. 

  • Urine; urination. 

  • A large town where theatrical performances may expect to achieve success. 

  • Used other than figuratively or idiomatically: see number, one. 

  • Oneself, being considered foremost, as by an egoist. 

  • Someone who is top of a ranking, who is ranked first. 

  • The single that has sold the most in a given period. 

  • A first lieutenant. 

adj
  • First; foremost; best, often used after its headword. 

How often have the words first base and number one occurred in a corpus of books? (source: Google Ngram Viewer )