Word Study
zygodactylous
CIDE DICTIONARY
zygodactylous, a. [Gr. zygo`n a yoke, pair + finger, toe: cf. F. zygodactyle.].
Yoke-footed; having the toes disposed in pairs; -- applied to birds which have two toes before and two behind, as the parrot, cuckoo, woodpecker, etc. [1913 Webster]
For further exploring for "zygodactylous" in Webster Dictionary Online