lamb vs Persian lamb

lamb and Persian lamb both are nouns.

Word	Noun	Adjective	Verb	Adverb
lamb	Yes	No	Yes	No
Persian lamb	Yes	No	No	No

As nouns, Persian lamb is a hyponym of lamb; that is, Persian lamb is a word with a more specific, narrower meaning than lamb:

Other hyponyms of lamb include lambkin, baa-lamb, hog, hogg, hogget, teg.

lamb (noun)	Persian lamb (noun)
young sheep	a karakul lamb
the flesh of a young domestic sheep eaten as food	the fur of a karakul lamb
a sweet innocent mild-mannered person (especially a child)
a person easily deceived or cheated (especially in financial matters)

lamb (verb)	Persian lamb (verb)
give birth to a lamb