Bonjour, Jackie--

dactyl
\Dac"tyl\, n. [L. dactylus, Gr. da`ktylos a finger, a dactyl. Cf. Digit.] 1. (Pros.) A poetical foot of three sylables (--- [crescent] [crescent]), one long followed by two short, or one accented followed by two unaccented; as, L. t["e]gm[i^]n[e^], E. mer\b6ciful; -- so called from the similarity of its arrangement to that of the joints of a finger. [Written also dactyle.]
2. (Zo["o]l.) (a) A finger or toe; a digit. (b) The claw or terminal joint of a leg of an insect or crustacean.
Source: Webster's Revised Unabridged Dictionary, © 1996, 1998 MICRA, Inc.

Remember dactyls from "Listen my children and..." or "higgledy-piggledy"?
Who would've thought they had any relation to fingers? That must mean that trochee comes from a word meaning thumb.