equid vs Equus caballus

equid and Equus caballus both are nouns.

Word	Noun	Adjective	Verb	Adverb
equid	Yes	No	No	No
Equus caballus	Yes	No	No	No

As nouns, Equus caballus is a hyponym of equid; that is, Equus caballus is a word with a more specific, narrower meaning than equid:

equid: hoofed mammals having slender legs and a flat coat with a narrow mane along the back of the neck
Equus caballus: solid-hoofed herbivorous quadruped domesticated since prehistoric times

Other hyponyms of equid include horse, ass, mule, hinny, zebra, Equus quagga, quagga.

equid (noun)	Equus caballus (noun)
hoofed mammals having slender legs and a flat coat with a narrow mane along the back of the neck	solid-hoofed herbivorous quadruped domesticated since prehistoric times