poniard vs rondel

poniard

noun
  • A dagger typically having a slender square or triangular blade. 

verb
  • To stab with a poniard. 

rondel

noun
  • A long thin medieval dagger with a circular guard and a circular pommel (hence the name). 

  • A small round tower erected at the foot of a bastion. 

  • A metric form of verse using two rhymes, usually fourteen 8- to 10-syllable lines in three stanzas, with the first lines of the first stanza returning as refrain of the next two. 

  • A rondelle, (small) circular object. 

  • The verse form rondeau. 

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