before vowels pyr-, word-forming element form meaning "fire," from Greek pyr (genitive pyros) "fire, funeral fire," also symbolic of terrible things, rages, "rarely as an image of warmth and comfort" [Liddell & Scott], from PIE root *paewr- "fire." Pyriphlegethon, literally "fire-blazing," was one of the rivers of Hell.
word-forming element meaning "horn, horn-like part," from Latinized form of Greek keras (genitive keratos) "horn of an animal; horn as a substance," from PIE root *ker- (1) "horn, head."
also homoeo-, word-forming element meaning "similar to," Latinized from Greek homio-, from homoios "like, resembling, of the same kind; equal," related to or an expanded form of homos "one and the same" (from PIE root *sem- (1) "one; as one, together with").
before vowels myc-, word-forming element meaning "mushroom, fungus," formed irregularly from Latinized form of Greek mykēs "fungus, mushroom, anything shaped like a mushroom," a word of uncertain origin (Beekes doubts the traditional explanation that connects it to the source of mucus). The correct form is myceto- (mycet-).
word-forming element used since 18c. (but most productively in 20c.), "kind of, like but not really, as if," expressing some resemblance but implying a degree of fictitious or unreal quality or lack of some important feature; from Latin quasi "as if, as it were" (see quasi).