French door

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

• noun A door, usually one of a pair, of light construction with glass panes extending for most of its length.

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

• noun US A door, usually one of a pair, with glass panes that extend for most of its length.

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

• noun a light door with transparent or glazed panels extending the full length