zygodactylichttp://www.oed.com/dictionary/zygodactylic_adj%3Ftab%3Dmeaning_and_usezygodactylic, adj.
First published 1921; not fully revised

zygodactylicadjective

Ornithology.
  1. 1835–
    Stressed as zygodacˈtylic.
    1. 1835
      Feet which accomplish these purposes are all zygodactylic, or yoke-toed.
      C. F. Partington, British Cyclopaedia Natural History vol. I. 445/1

Originally published as part of the entry for zygodactyl, adj. & n.

zygodactyl, adj. & n. was first published in 1921; not fully revised.