As used in this article, the following terms shall have the meaning indicated:
A house, apartment, store or other building whether or not used or designated for use as a dwelling.
The family group occupying one dwelling unit.
A cat shall be considered public nuisance if it has no known owner or custodian, or if it has no known place of care or shelter, or if it trespasses upon and damages either private or public property or harms lawful users or occupants thereof.