As long as a bedroom has a window and is up to code, it is a bedroom.
Our former landlord tried to rent a 3 br./2 ba basement apt. w/o a window in one and no fire escape and that was a code violation on top of not fixing repairs and no heat on the cold winter months for 3 yrs straight.
A fine was imposed but was disregarded. So we all went and took him to L&T (landlord tenant) court.