BOB vs equivalent

BOB

adj
  • Back-of-the-book; denoting those stamps in a catalogue that are not used for the payment of regular postage fees, and are displayed separately in the catalogue after that listing; the division between these two groups varies with the publisher. 

noun
  • Vibrator (device designed to stimulate a woman's genitals). 

equivalent

adj
  • Of two sets, having a one-to-one correspondence. 

  • Having the equal ability to combine. 

  • Similar or identical in value, meaning or effect; virtually equal. 

  • Of a map, equal-area. 

  • Equal in measure but not admitting of superposition; applied to magnitudes. 

  • Relating to the corresponding elements of an equivalence relation. 

noun
  • An equivalent weight. 

  • Anything that is virtually equal to something else, or has the same value, force, etc. 

verb
  • To make equivalent to; to equal. 

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