"wing joint," c.1440, from M.Fr. pignon (c.1400), from V.L. *pinnionem, from L. penna "wing" (see pen (1)). Verb meaning "disable by binding the arms" is from 1558, older than lit. sense "cut the pinions of a wing to prevent a bird from flying" (1577).
"small gear with teeth" (as in rack and pinion), 1659, from Fr. pignon, from O.Fr. pignon "crenellation, battlement," aug. of L. pinna "battlement, pinnacle;" confused with (but perhaps ult. a variant of) penna "wing, feather, peak" (see pen (1)).