emergency-n; 3 Senses

Sense Number 1: an immediate, unforeseen crisis, often dangerous

Commentary: EMERGENCY[+event][+crisis][+immediate][-foreseen]
NOTE: does not imply a mandated a state of need for a community (see Sense 2)
NOTE: implies an unexpected, serious event requiring immediate attention.

Call this number in case of emergency.
This can wait until tomorrow, it's not an emergency.
The plane made an emergency landing in Omaha.
The senator was rushed into emergency following the accident. (emergency room)
It's becoming an emergency situation with their currency devaluation.
They called an emergency session of Congress.

WordNet 3.0 Sense Numbers: 1

Sense Number 2: an officially decreed state of need

Commentary: EMERGENCY[+state][+mandated][+officially][+need]
NOTE: implies an authority has officially declared a temporary state of need in a community

The governor has declared a state of emergency in three counties following the storm.
Curfew has been imposed during this state of emergency.
The state of emergency in the city finally ended on Friday.

WordNet 3.0 Sense Numbers: 2

Sense Number 3: a hand brake

Commentary: EMERGENCY[+device][+brake][+hand]

The student driver forgot to release the emergency before backing the car.
He discovered the emergency brake did not work while trying to park on a hill.

WordNet 3.0 Sense Numbers: 3