Real Dictionary

ruminant in American English
any of the suborders (Ruminantia and Tylopoda) of four-footed, cud-chewing artiodactylous mammals: cattle, buffalo, goat, deer, antelope, and giraffe have a stomach with four chambers (the rumen, reticulum, omasum, and abomasum) and the camel, llama, and
chewing the cud
adjective: ruminating; chewing the cud
noun: any even-toed, hoofed mammal of the suborder Ruminantia, being comprised of cloven-hoofed, cud-chewing quadrupeds, and including, besides domestic cattle, bison, buffalo, deer, antelopes, giraffes, camels, and chevrotains

ruminant in British English
adjective: of, relating to, or belonging to the suborder Ruminantia
noun: any artiodactyl mammal of the suborder Ruminantia, the members of which chew the cud and have a stomach of four compartments, one of which is the rumen. The group includes deer, antelopes, cattle, sheep, and goats