(a) As used in this part:
(1) Includes means including but not limited to;
(2) May means is permitted to or is authorized to;
(3) May not means is not permitted to or is not authorized to; and
(4) Shall or must is used in the mandatory and imperative sense.
(b) In this part:
(1) Words importing the singular include the plural; and
(2) Words importing the plural include the singular.