n. Any animal of the taxonomic family Equidae, including any equine (horse, zebra, ass, mule, etc.)
The Century Dictionary and Cyclopedia
n. A hoofed mammal of the family Equidæ.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. hoofed mammals having slender legs and a flat coat with a narrow mane along the back of the neck
Word Usage
"Years ago, the famous professor George Simpson wrote, “The most famous of all equid horse trends, ‘gradual reduction of the side toes,’ is flatly fictitious.”"