emergency vs hand brake

emergency and hand brake both are nouns.

Word	Noun	Adjective	Verb	Adverb
emergency	Yes	No	No	No
hand brake	Yes	No	No	No

As nouns, emergency and hand brake are synonyms defined as:

emergency and hand brake: a brake operated by hand; usually operates by mechanical linkage

Other synonyms of emergency include emergency brake, parking brake.

emergency (noun)	hand brake (noun)
a brake operated by hand; usually operates by mechanical linkage	a brake operated by hand; usually operates by mechanical linkage
a sudden unforeseen crisis (usually involving danger) that requires immediate action
a state in which martial law applies