bear's breech vs bear's breeches

bear's breech and bear's breeches both are nouns.

Word	Noun	Adjective	Verb	Adverb
bear's breech	Yes	No	No	No
bear's breeches	Yes	No	No	No

As nouns, bear's breech and bear's breeches are synonyms defined as:

bear's breech and bear's breeches: widely cultivated southern European acanthus with whitish purple-veined flowers

Other synonyms of bear's breech include Acanthus mollis, sea holly.

bear's breech (noun)	bear's breeches (noun)
widely cultivated southern European acanthus with whitish purple-veined flowers	widely cultivated southern European acanthus with whitish purple-veined flowers