Priapeun or Priapean: How To spell?

The word Priapeun is misspelled against Priapean, a noun meaning "A species of hexameter verse so constructed as to be divisible into two portions of three feet each, having generally a trochee in the first and the fourth foot, and an amphimacer in the third; -- applied also to a regular hexameter verse when so constructed as to be divisible into two portions of three feet each."