softball vs volleyball

softball

noun
  • The ball used to play the sport. 

  • A question designed to be easy to answer. 

  • A game similar to baseball but played with a larger and softer ball which can be thrown overhand or underhand. 

volleyball

noun
  • The inflated ball used in such a game. 

  • A game played on a rectangular court between two teams of two to six players which involves striking a ball back and forth over a net. 

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