mainstream vs thought

mainstream and thought both are nouns.

Word	Noun	Adjective	Verb	Adverb
mainstream	Yes	No	No	No
thought	Yes	No	No	No

As nouns, thought is a hypernym of mainstream; that is, thought is a word with a broader meaning than mainstream:

mainstream (noun)	thought (noun)
the prevailing current of thought	the process of using your mind to consider something carefully
	the content of cognition; the main thing you are thinking about
	the organized beliefs of a period or group or individual
	a personal belief or judgment that is not founded on proof or certainty