Exclusive disjunction

An “or” that means either this or that but not both.

This is an unusual type of or. Most ors are inclusive disjunctions, meaning “it could be this, that, or both: I’m honestly relaxed and don’t care as long as one of you shows up.”

If you have an inclusive or, as mostly you should, you don’t need an and/or. If (you think) you have an exclusive or, and you need an and, just use an inclusive or.