a stream of water, as a river or brook.

the bed of a stream that flows only seasonally.

a natural channel conveying water.

a channel or canal made for the conveyance of water.

noun

aqueduct , brook , canal , channel , chute , conduit , creek , culvert , drain , estuary , flume , gullet , gully , gutter , inlet , ravine , river , sluice , spillway , stream , trench , wadi