knee breeches vs breeches

knee breeches and breeches both are nouns.

Word	Noun	Adjective	Verb	Adverb
knee breeches	Yes	No	No	No
breeches	Yes	No	No	No

As nouns, knee breeches and breeches are synonyms defined as:

knee breeches and breeches: (used in the plural) trousers ending above the knee

Other synonyms of knee breeches include knee pants, knickerbockers, knickers.

knee breeches (noun)	breeches (noun)
(used in the plural) trousers ending above the knee	(used in the plural) trousers ending above the knee