amyl vs pentyl

amyl

adj
  • Of or pertaining to starch 

noun
  • amyl nitrite 

pentyl

noun
  • Any of several isomeric univalent hydrocarbon radicals, C₅H₁₁, formally derived from pentane by the loss of a hydrogen atom. 

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