pentadactylPronunciation: /ˌpɛntəˈdaktɪl/Definition of pentadactyl adjective Zoology (of a vertebrate limb) having five toes or fingers, or derived from such a form, as characteristic of all tetrapods. Derivatives pentadactylyPronunciation: /-ˈdaktɪli/ noun Origin: early 19th century: from penta- 'five' + Greek daktulos 'finger'pentadactyl in other Oxford dictionaries Definition of pentadactyl in the US English dictionary