riding breeches vs trousers

riding breeches and trousers both are nouns.

Word	Noun	Adjective	Verb	Adverb
riding breeches	Yes	No	No	No
trousers	Yes	No	No	No

As nouns, trousers is a hypernym of riding breeches; that is, trousers is a word with a broader meaning than riding breeches:

riding breeches: (used in the plural) flared trousers ending at the calves; worn with riding boots
trousers: (usually in the plural) a garment extending from the waist to the knee or ankle, covering each leg separately

Other hypernyms of riding breeches include pair of trousers, pant.

riding breeches (noun)	trousers (noun)
(used in the plural) flared trousers ending at the calves; worn with riding boots	(usually in the plural) a garment extending from the waist to the knee or ankle, covering each leg separately