I found myself reading about the Archaeopteryx at Wikipedia for some reason. It's all scientific and very bracing. But of course there's the usual ignorance about Greek and Latin, which always fills me with sorrow: "pteryx = variously translated as wing, feather, or more specifically pinion". It means "wing". Ptera are "feathers". (English "feather" also used to mean "wing" and is a cognate of this word). Petomai is "fly" or "rush". There is of course some transference here and there, so epea pteroenta are "winged words" rather than "feathered words", but we can deduce a lot about the priority of meanings from word endings and from what we know about word-formation, related roots in other languages, and usage.

It seems reasonable to think of pteryx as "an organ of flight", from petomai, on the analogy of pharynx, "throat", from pharo "part, or separate". Nouns in -yx, -ynx, or -inx often mean a thing that does something. Kerygma is "a proclamation", the object of kerytto, "proclaim", but keryx is "a herald". Kokkyx is "a cuckoo" because it goes "kokku!" And that's how you know it's spring and time to write a letter to the Times.