(a) As used in this chapter, unless the context otherwise requires:

(1) “Tenement house” means any house or building, or portion thereof, which is rented, leased, let or hired out to be occupied, or is arranged or designed to be occupied, or is occupied, as the home or residence of three or more families, living independently of each other, and doing their cooking upon the premises, and having a common right in the halls, stairways or yards;

(2) “Lodging house” or “boarding house” means any house or building or portion thereof, in which six or more persons are harbored, received or lodged for hire, or any building or part thereof, which is used as a sleeping place or lodging for six or more persons not members of the family residing therein;

(3) “Apartment” means a room or suite of rooms occupied or designed to be occupied as a family domicile;

(4) “Yard” means an open, unoccupied space, on the same lot with a tenement, lodging or boarding house, between the rear line of such house and the rear line of the lot;

(5) “Court” means an open, unoccupied space, other than a yard, on the same lot with a tenement house;

(6) “Basement” means a story partly, but not more than one-half, below the level of the grade; and

(7) “Cellar” means a story more than one-half below the level of the grade.

(b) For purposes of this chapter, the word “shall” is mandatory and not directory, and denotes that the house shall be maintained in all respects according to the mandate, as long as it continues to be a tenement house.

(c) In determining the number of stories in a tenement house, a basement or an attic shall be counted as a story if it is occupied or designed to be occupied for living purposes.