What is the meaning of Mainstream?

Used or accepted broadly rather than by small portions of population, market, scientific community, etc.

The principal current in a flow, such as a river or flow of air

That which is common; the norm.

To popularize, to normalize, to render mainstream.

To become mainstream.

To educate (a disabled student) together with non-disabled students.

mainstream (dominant way of thinking or the most popular form of action)

mainstream jazz (term coined in the 1950s by music journalist Stanley Dance, who considered anything within the popular jazz of the Swing Era "mainstream", and did not include the bebop style)

mainstream

Source: wiktionary.org