thought vs notion

thought and notion both are nouns.

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

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

thought (noun)	notion (noun)
the process of using your mind to consider something carefully	(usually plural) small personal articles or clothing or sewing items
the content of cognition; the main thing you are thinking about	a general inclusive concept
the organized beliefs of a period or group or individual	an odd or fanciful or capricious idea
a personal belief or judgment that is not founded on proof or certainty	a vague idea in which some confidence is placed