couplet vs ode

couplet

noun
  • A pair of lines, typically with rhyming end words. 

  • A pair of one-way streets which carry opposing directions of traffic through gridded urban areas. 

  • A pair of two mutually exclusive choices in a dichotomous key. 

ode

noun
  • A short poetical composition proper to be set to music or sung; a lyric poem; especially, now, a poem characterized by sustained noble sentiment and appropriate dignity of style. 

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