mainstem

listen to the pronunciation of mainstem
Английский Язык - Английский Язык
The main channel of a river, as opposed to the streams and smaller rivers that feed into it
The main course of a stream
the main channel of the river in a river basin
The main channel of a river -- as opposed to the streams and smaller rivers that feed into it
The principle stream or river of a particular basin
The major reach of a river or stream formed by the smaller tributaries which flow into it
The principle stream or River of a particular basin The Chehalis River is the mainstem of the Chehalis Basin
The main course of a river or stream where most of the water flows most of the time