1) A gate which could open or close a channel through which water flowed, a sluice.
It will sometimes be evidence that controlled flooding of riverside meadows was taking place. A very early but undated reference is flodeyhaytes de Suttondyk, in the Chronica Monasterii de Melsa. Probably later are: 1364 ‘les flodyates of the mill’, Thorner
1476 milnedammes, lokkes, hebbyng weres, piles, hekks, flodeyates and all other impediments, York. It remained in common use: 1788 making and using flood gates, store-bays and other works, Hunsworth
1474 flodeyates alias voc’ flodeheckes, Wakefield.