What is a disjunctive conjunction?
The disjunctive conjunction is "or" when used to provide mutually exclusive possibilities.
English does not have a clear disjunctive conjunction. The word "or" is often used to serve this function BUT the English "or" is used with both the inclusive (one or the other or both) and exclusive (one or the other but not both). The disjunctive conjunction should only be applied with the exclusive meaning.