swivel chair

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A chair that swivels on its base.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A chair with a rotating seat, typically used in an office or at a computer.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a chair that swivels on its base