stria vs underscore

stria

noun
  • A stripe, usually one of a set of parallel stripes. 

  • A stretch mark. 

  • One of the fillets between the flutes of columns, etc.. 

underscore

noun
  • An underline; a line drawn or printed beneath text; the character _. 

  • A piece of background music. 

verb
  • To emphasize or draw attention to. 

  • To underline; to mark a line beneath text. 

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