emergency

nouns

a sudden unforeseen crisis (usually involving danger) that requires immediate action
"he never knew what to do in an emergency"
emergency, exigency, pinch
is derived from
emergent
a state in which martial law applies
"the governor declared a state of emergency"
emergency
is a type of (narrower)
a state that continues for a limited time
temporary state
a brake operated by hand; usually operates by mechanical linkage
emergency, emergency brake, hand brake, parking brake