The Collaborative International Dictionary
Anisodactylous
Anisodactylous \An`i*so*dac"ty*lous\, a. (Zo["o]l.) Characterized by unequal toes, three turned forward and one backward, as in most passerine birds.
Wiktionary
anisodactylous
a. (context zoology English) Characterized by unequal toes, three turned forward and one backward, as in most passerine birds.