ac- vs iso-

ac-

prefix
  • oak. 

  • to or with. 

iso-

prefix
  • Isomer. 

  • Equal; equivalent. 

  • Forms terms for specific kinds of isolines. 

  • Same, identical. 

  • (of an aliphatic compound, especially a fatty acid) Having a branch on the penultimate carbon atom of a chain. 

  • Isomorphism. 

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