This is an irregular feature - both in frequency and oddness - dedicated to a word I came across that I have never previously used.
pergameneous (pehr-guh-MEE-nee-uhs) adj. pertaining to or resembling parchment.
"Pergameneous" is derived from the Latin word pergamena, meaning "parchment." The Latin word, in turn, traces its origin to the Greek city of Pergamon, which was a major source of parchment paper in classical times. The term "pergameneous" is occasionally used in biology to describe surfaces that resemble parchment in texture.