'floodgate' definitions:

Definition of 'floodgate'

From: WordNet
noun
Something that restrains a flood or outpouring; "suspension of surveillance opened the floodgates to illegal immigrants"
noun
Regulator consisting of a valve or gate that controls the rate of water flow through a sluice [syn: sluicegate, sluice valve, floodgate, penstock, head gate, water gate]