A cervid is a deer or one of its very close relatives. Cervids have hooves and antlers.
Next time you see a moose, elk, or reindeer, you can say, "Hey, there's a cervid!" These members of the taxonomic family Cervidae are colloquially known as deer. They include animals with hard hooves, and in the case of adult males, large antlers (female caribou have them too). Like cows, cervids are ruminants who chew grasses that get fermented in an extra stomach before being digested. The Latin root of cervid is cervus, "deer."