hydraulic brakes vs hydraulic brake cylinder

hydraulic brakes and hydraulic brake cylinder both are nouns.

Word	Noun	Adjective	Verb	Adverb
hydraulic brakes	Yes	No	No	No
hydraulic brake cylinder	Yes	No	No	No

hydraulic brakes (noun)	hydraulic brake cylinder (noun)
brake system in which a brake pedal moves a piston in the master cylinder; brake fluid then applies great force to the brake pads or shoes	a cylinder that contains brake fluid that is compressed by a piston