ringlet vs seal ring

ringlet

noun
  • A small ring. 

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

  • A lock, tress. 

verb
  • To surround or encircle like a ringlet. 

  • To form into ringlets. 

seal ring

noun
  • A finger ring with an engraved (often heraldic) seal, fit for sealing documents by pressing it in sealing wax or a similar substance 

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