Real Dictionary

cellar
countable noun: A cellar is a room underneath a building, which is often used for storing things in.

cellar in American English
a room or group of rooms below the ground level and usually under a building, often used for storing fuel, provisions, or wines
to store in a cellar
noun: a room, or set of rooms, for the storage of food, fuel, etc., wholly or partly underground and usually beneath a building
transitive verb: to place or store in a cellar

cellar in British English
noun: an underground room, rooms, or storey of a building, usually used for storage
verb: to store in a cellar

cellar in the Oil and Gas Industry
noun: A cellar is a dug-out area below a rig that houses the top part of the casing.