In wireless telcommunications, a cell can be thought of as the area served by one base station. In practice, that association doesn't need to be one-on-one, depending on what you classify as "base station". One point, though, should be mentioned: telecommunication cells usually cover an area (of various size) up to a height of a few hundred meters (at most) - which is one reason why you shouldn't use a cellular phone on an airplane.