What is main difference in meaning and usage between genius and ingenious?
Someone who is a genius has exceptional intellectual or creative ability.

Someone who is ingenious is original and inventive.

They do not have the same derivation.

genius = ORIGIN Latin, also in the sense ‘spirit present at one’s birth’, from gignere ‘beget’
ingenious = ORIGIN Latin ingeniosus, from ingenium ‘mind, intellect’; related to "Engine".
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I think igenious is a sub-set of genius! Not all genius's are ingenious.. A genius innovater can be reffered to as ingenious...
Genius is a noun. It is most commonly used to describe a person having an extraordinarily high intelligence rating on a psychological test, as an IQ above 140; or to describe an exceptional natural capacity of intellect, especially as shown in creative and original work in science, art, music (e.g. the genius of Mozart) Ingenious is an adjective. It is used to describe the quality of cleverness or originality of invention or construction (e.g. an ingenious machine).
it is indeed a subset just as who is to whom it has to do with the oject and while they can mean diffrent things they are commonly used as alike.
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If it were a sub-set it would look like this

All Geniuses:
[ [Ingenious] Not Ingenious ]

...meaning all geniuses are ingenious.
Genius (Greek =γενιά ,γενιμενος)=birth meaning born smart.
Ingenious (Greek = ΕΝΓΕΝΙΑ = engenia )=celebration of something new
The difference is only the word class. Genius is a noun while ingenious is an adjective. Ingeniousness however a noun.
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