before vowels ornith-, word-forming element meaning "bird, birds," from combining form of Greek ornis (genitive ornithos; plural ornithēs) "a bird," in Attic generally "domestic fowl, cock or hen," which often was added to the specific name of the type of bird, from PIE *or- "large bird" (see erne).

For "bird" Greek also had ptēnon (plural peteina), related to pteron "wing," from the root meaning "to fly."