spout; water outlet
Refers to the mouth or opening from which water flows. It is more specific and less everyday than words such as 蛇口 for a faucet or 注ぎ口 for the spout of a container.
水口から水が勢いよく流れ出た。
Water gushed out from the spout.
水口に落ち葉が詰まっている。
Fallen leaves are clogging the water outlet.
Water is drawn in through the inlet of the rice field.
He opened the water inlet to let water into the field.
He blocked the water outlet to stop the flow.