coin flip vs fifty-fifty

coin flip

noun
  • Synonym of coin toss 

fifty-fifty

adj
  • Half and half. 

  • Used to describe 2 possible outcomes as being equally likely 

noun
  • A challenge between two opposing players, where both have an equal chance of taking possession. 

adv
  • In half: in two equal parts, shares, etc. 

How often have the words coin flip and fifty-fifty occurred in a corpus of books? (source: Google Ngram Viewer )