Dactyl n. : A poetical foot of three sylables (-- ~ ~), one long followed by two short, or one accented followed by two unaccented; as, L. tegm/n/, E. mer\b6ciful; -- so called from the similarity of its arrangement to that of the joints of a finger.

Dactyl n. : A finger or toe; a digit.

Dactyl n. : The claw or terminal joint of a leg of an insect or crustacean.

Example:
Why is the iphone app Dactyl called Dactyl?

Taxonomy
Dactyl, free encyclopedia, finger, Greek word, search, creature, Pterodactyl, flying, Triassic, Cretaceous Period, metrical foot, long syllable, Catherine, segment, medical terminology, Greek, movable, pincers.

Defination from the web:
Dactyl (poetry), a metrical foot consisting of one long syllable and two short as in "Catherine. ... Dactyl (moon), the small natural satellite orbiting the asteroid Ida. Finger, in medical terminology, from the Greek δάκτυλος. The movable part of crustacean claws/pincers. ...