(a) A single-family dwelling is a detached building designed for or occupied by one family exclusively.
(b) A two-family dwelling is a detached building designed for or occupied by two (2) families.
(c) A multi-family dwelling is a building designed for or occupied by three (3) or more families, exclusively for dwelling purposes.
(d) A townhouse is a structure containing two (2) or more single-family dwellings which are attached by a common party wall designed for or occupied by one family exclusively. Regardless of the further contrary provisions hereof, side yard setoffs are not required for interior townhouses. End unit townhouses are subject to the same side yard requirements as other residential structures in the same area or zone. Front and rear yard requirements for townhouses are the same as for other residential structures in the same area or zone. (1969 Code §27-17; 4-21-77)