For the purpose of these Regulations, certain words and terms are defined as follows: Words used in the present tense include the future; words in the singular number include the plural, and vice versa; the word “shall” is mandatory and not discretionary, and the word “may” is permissive; the word “person” includes individuals, partnerships, corporations, clubs or associations; the word “structure” includes the word “building”. (Prior code § 12-2-1)