For the purpose of this ordinance, the definitions listed in Appendix “A” shall be used unless otherwise specified. Words used in the present tense include the future; the singular number includes the plural number; and the plural number includes the singular number. The word “shall” is mandatory and not directory. Words not defined in Appendix “A” shall be construed according to any applicable definition set forth in either the State Statutes, Administrative Code or County Ordinance or in lieu thereof, shall be construed according to accepted land use, scientific, or architectural definition or in lieu thereof, according to their customary dictionary definition. [Code § 12.02-15.]