main stream; main course
Refers to the primary channel or flow of a river, as opposed to tributaries or branches.
The main stream of this river continues deep into the mountains.
noun, noun which may take the genitive case particle 'no'
Used figuratively for the dominant trend, school of thought, or movement in a field. Often appears as 本流の～ or ～の本流.
His way of thinking deviates from the mainstream of modern philosophy.
This writer is one of the representatives of the mainstream of Japanese literature.
The main stream of the Tone River flows through the Kanto Plain.
This tributary joins the main stream further downstream.
He is a researcher who carries on the mainstream tradition of that school of thought.
That way of thinking departs from the political mainstream.