sweet pepper plant vs pimento

sweet pepper plant and pimento both are nouns.

Word	Noun	Adjective	Verb	Adverb
sweet pepper plant	Yes	No	No	No
pimento	Yes	No	No	No

As nouns, sweet pepper plant and pimento are synonyms defined as:

sweet pepper plant and pimento: plant bearing large mild thick-walled usually bell-shaped fruits; the principal salad peppers

Other synonyms of sweet pepper plant include bell pepper, Capsicum annuum grossum, paprika, pimiento, sweet pepper.

sweet pepper plant (noun)	pimento (noun)
plant bearing large mild thick-walled usually bell-shaped fruits; the principal salad peppers	fully ripened sweet red pepper; usually cooked
	plant bearing large mild thick-walled usually bell-shaped fruits; the principal salad peppers