Topic summary
Watercourse

Extracted from the Wikipedia article Stream.
A stream is a continuous body of surface waterflowing within the bed and banks of a channel. The channel is a watercourse, although the watercourse may be seasonally or periodically dry. Depending on its location or certain characteristics, a stream may be referred to by a variety of local or regional names. Long, large streams are usually called rivers, while smaller, less voluminous and more intermittent streams are known, amongst others, as brook, creek, rivulet, rill, run, tributary, feeder, freshet, narrow river, and streamlet.