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Webster 1913 Edition
Pachydermata
‖
Pachˊy-der′ma-ta
(păkˊĭ-dẽr′mȧ-tȧ)
, Noun.
 pl.
 [NL., fr. Gr. 
παχύδερμοσ 
thick-skinned; παχύσ 
thick + δέρμα 
skin.] (Zool.) 
A group of hoofed mammals distinguished for the thickness of their skins, including the elephant, hippopotamus, rhinoceros, tapir, horse, and hog; the pachyderms. It is now considered an artificial group.