1. A gate used to control the flow of a body of water. Also called water gate.
2. Something that restrains a flood or outpouring: The ruling opened the floodgates to refugees seeking asylum.

The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.