Individual has one of the more interesting etymologies I’ve come across. It has quite a variety of words as relatives, some I’m betting you won’t expect.
The adjective form first showed up in the early fifteenth century, however with a slightly different meaning. It had a religious context to it, referring to the “one and indivisible” Trinity, not taking on the modern meaning until the early seventeenth century. The noun individual showed up in the sixteenth century referring to a separate object. A human wasn’t known as an individual until 1742.
Individual comes from the Medieval Latin individualis or the classical Latin individuus. Either way, it’s an amalgamation of prefixes. The in-, a fairly common mutation of the prefix un-, means not or opposite. Which makes sense because an individual is certainly not dividable.
And that brings us to the divide part. The di- is another prefix, a variation of dis-, which means apart. That leaves us with -vide. It comes from the classical Latin videre, meaning “to separate.” So with dis-, that makes it “to separate apart”, and then adding in that in- makes it “not to separate apart”, or something that cannot be separated.
But we aren’t quite done yet. See, videre is where it gets interesting. It comes from the Proto-Indo-European weidh, again meaning “to separate”. Weidh is also the ancestor of widow (via Proto Germanic) and, here’s the shocker, is a distant relative of with. It might seem strange, but long ago with once meant the literal opposite of what it does now. Weidh comes from wi-, separation, and with comes from wi-tero-, “more apart”. As to why it changed meanings…I don’t know. Peer pressure?
We’ve got to start writing down why we change words’ meanings when it happens. It will save future etymologists a lot of guesswork.
Dr. Rebecca R. Harrison’s page at Truman State University