Pachydermata (păk&ibreve_;d&etilde_;rm&adot_;t&adot_;), n. pl. [NL., fr. Gr. pachydermos thick-skinned; pachys thick + derma skin.] (Zoöl.) 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.[1913 Webster]