ringlet vs undulate

ringlet

verb
  • To surround or encircle like a ringlet. 

  • To form into ringlets. 

noun
  • Any of various butterflies with small rings on the wings, in the tribe Satyrini of the family Nymphalidae, such as Aphantopus hyperantus. 

  • A small ring. 

  • A lock, tress. 

undulate

verb
  • To appear wavelike. 

  • To cause to resemble a wave 

  • To cause to move in a wavelike motion. 

  • To move in wavelike motions. 

adj
  • Changing the pitch and volume of one's voice. 

  • Wavy in appearance or form. 

  • sinuous, winding up and down. 

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