Not really sure what you mean but as Origumi has pointed out, the Arabic ذهن has found its way into many languages.ذهن has very few meanings and it seemed it could be a loan-word from another language. Do you have any idea about that?
As a second question do you recommend it to use a counterpart of Ancient Greek "nous"?
There are two few 3-letters combinations to justify such claim unless there's a clear connection between the roots meaning. For example, how mind and gold are similar? Also, it's important to show that the roots were'nt different originally and becames similar as a result of sound shifts.You can know by comparing the root to other similar roots in the same language. There are many roots in Arabic similar to this root phonologically and semantically, so it must be native and ancient one.
This is well said, Maha. I also want to point to those obviously very old words like يد and دم, which have no other derivatives مشتق than one or two corresponding adjectives.Besides, it can be purely Arabic, but more recent than other roots - we are allowed to invent new words and classify them under new roots you know.