The Collaborative International Dictionary
Water gate
Water gate \Wa"ter gate`\ A gate, or valve, by which a flow of water is permitted, prevented, or regulated.
Wiktionary
water gate
n. A gate, or valve, by which a flow of water is permitted, prevented, or regulated.
WordNet
water gate
n. 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]