- sluicegate, sluice valve, floodgate, penstock, head gate, water gate - regulator consisting of a valve or gate that controls the rate of water flow through a sluice
--1 is a kind of regulator
--1 is a part of sluice, sluiceway, penstock - head gate - a gate upstream from a lock or canal that is used to control the flow of water at the upper end
--2 is a kind of gate