upsilon vs wye

upsilon

noun
  • The twentieth letter of Classical and Modern Greek; the twenty-second letter of Old and Ancient Greek. 

  • An upsilon meson, or bottomonium. 

wye

noun
  • The name of the Latin-script letter Y. 

  • A Y-shaped object: a wye level, wye-connected. Especially a Y-shaped connection of three sections of road or railroad track. 

verb
  • To reverse the direction of a train using a wye. 

  • To make something into a wye (letter Y) shape. 

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