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
Plain English Anatomy™ Noun | Verb | Adjective | Adverb | Preposition | Conjunction | Latin | Germany | Flannel | Legal triplicate | Nominalisation | Murder your darlings