disjunctive proposition a proposition whose main propositional operator (main connective) is the disjunction operator, i.e., the logical operator that represents ‘and/or’. Thus, ‘(P-and/or- Q)-and-R’ is not a disjunctive proposition because its main connective is the conjunction operation, but ‘P-and/or-(Q-and-R)’ is disjunctive. R.W.B.