The Collaborative International Dictionary of English v.0.48:

Artiodactyla \Ar`ti*o*dac"ty*la\, n. pl. [NL., fr. Gr. ? even +
   ? finger or toe.] (Zool.)
   One of the divisions of the ungulate animals. The functional
   toes of the hind foot are even in number, and the third digit
   of each foot (corresponding to the middle finger in man) is
   asymmetrical and paired with the fourth digit, as in the hog,
   the sheep, and the ox; -- opposed to Perissodactyla.
   [1913 Webster]

WordNet (r) 3.0 (2006):

Artiodactyla
    n 1: an order of hooved mammals of the subclass Eutheria
         (including pigs and peccaries and hippopotami and members
         of the suborder Ruminantia) having an even number of
         functional toes [syn: Artiodactyla, order Artiodactyla]