[[A polar question construction is a sentence whose expected answer is one of two choices.]]
polarity question (a.k.a. Y/N question, yes/no question) (INF/CXN) = an interrogative in which the unknown piece of the propositional content requested of the addressee is the polarity (positive or negative) of the proposition; and the construction expressing this function. Example: Are you coming? is an instance of the English polarity question construction, expecting a ‘yes’ or ‘no’ answer. (Section 12.3.1)