29. Structure shall mean a building or construction of any kind.
30. Alteration, as applied to a building or structure, shall mean any change or rearrangement in the structural parts or in the existing facilities of any such building or structure, or any enlargement thereof, whether by extension on any side or by any increase in height, or the moving of such building or structure from one location or position to another.
31. A multiple dwelling is fireproof if the walls and structural members thereof meet the fire-resistive standards set forth in subdivision twenty-five of section four of the multiple dwelling law. Any other multiple dwelling is nonfireproof. A part of a dwelling is fireproof if it meets the standard set forth in the multiple dwelling law for the corresponding part of a fireproof dwelling.
32. Fire-retarded shall mean either covered with metal lath plastered with two or more coats of mortar or otherwise protected against fire in a manner approved by the department with materials of standard fire-resistive ratings of at least one hour. Fireproofing shall always be accepted as meeting any requirement for fire-retarding.
33. A rear yard is an open space on the same lot with a dwelling between the extreme rear line of the lot and the extreme rear wall of the dwelling. A side yard is a continuous open space on the same lot with a dwelling between the wall of a dwelling and a line of the lot from the street to a rear yard or rear line of a lot.
34. A court is an open space other than a side or rear yard, on the same lot as a dwelling. A court not extending to the street or rear yard is an inner court. A court extending to the street or rear yard is an outer court.