Longman Dictionary of Contemporary English
Wiktionary
n. An underground structure used to shelter from storms that have high winds, such as a tornado.
WordNet
n. an underground shelter where you can go until a storm passes [syn: cyclone cellar, tornado cellar]
Wikipedia
A storm shelter or storm cellar is a type of underground bunker designed to protect the occupants from violent severe weather, particularly tornadoes. They are most frequently seen in the Midwest (" Tornado Alley") and Southeast United States where tornadoes are generally frequent and the low water table permits underground structures.
Usage examples of "storm cellar".
She was a woman full of tornadoes waiting to happen, and if he had been a farmer observing a sky which looked the way Annie's face looked right now, he would have at once gone to collect his family and herd them into the storm cellar.
Calling Bobbi Anderson on the phone and saying: I almost went up in the cyclone, Bobbi, but I found the storm cellar just in time.
The next instant the door of the storm cellar banged open, letting in a flood of dazzling white light that made Nick raise a hand to shield his good eye.
Little Red Pest dashed up out of the storm cellar stairs, winding herself around Arona's legs.
Reaching the end of the passageway, the caretaker switches off the flashlight, and the moonless dark closes over them as if they have descended into a storm cellar and pulled the door shut at their backs.