thought vs keynote

thought and keynote both are nouns.

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

As nouns, keynote is a hyponym of thought; that is, keynote is a word with a more specific, narrower meaning than thought:

thought (noun)	keynote (noun)
the process of using your mind to consider something carefully	a fundamental or central idea
the content of cognition; the main thing you are thinking about	(music) the first note of a diatonic scale
the organized beliefs of a period or group or individual	the principal theme in a speech or literary work
a personal belief or judgment that is not founded on proof or certainty

thought (verb)	keynote (verb)
	set the keynote of
	give the keynote address to (an audience)