noun.
An adjustable gate or valve used to control the flow of water through a sluice.
noun.
Anything that controls or limits an outpouring of people, emotion etc.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
noun.
regulator consisting of a valve or gate that controls the rate of water flow through a sluice
noun.
something that restrains a flood or outpouring
Word Usage
"Despite Senator Murkowski's claims of urgency to stop the "floodgate" of greenhouse gas pollution reductions EPA is poised to "unleash," she plans to bide her time for maximum political - and perhaps campaign - advantage."