'mainstreamer' originates from the English word 'mainstream,' which comes from the combination of 'main' and 'stream,' where 'main' meant 'principal' and 'stream' referred to a current or flow.

'mainstream' evolved from the Middle English word 'main' and 'stream,' eventually forming the modern English word 'mainstreamer' to describe someone who follows the mainstream.

Initially, 'mainstream' referred to the principal current of a river, but over time it evolved to mean the dominant trend or direction in society.