Zoology having ten rays or fingers ( New Sydenham Soc. Lexicon). [ < scientific Latin decadactylus (1764 or earlier) < ancient Greek δεκαδάκτυλος ten fingers long or wide, in Hellenistic Greek also having ten fingers < δεκα-deca-comb. formδάκτυλος finger (see dactylo-comb. form); compare French decadactyle (1808 or earlier).]