Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
‡ pē̆trōtos, on, adj. [πετρόω], stony, petrified: quae modicos calices duos quos appellabant petrotos HS. V[dibreve]I = . venderet, Plin. 36, 26, 66, § 195 Jan. (dub.; al. pterotos).