TTB. The Alcohol and Tobacco Tax and Trade Bureau, Department of the Treasury, Washington, DC.
27 CFR § 13.11
Where used in this part and in forms prescribed under this part, where not otherwise distinctly expressed or manifestly incompatible with the intent thereof, terms shall have the meaning ascribed in this subpart. Words in the plural form shall include the singular, and vice versa, and words importing the masculine gender shall include the feminine. The terms include and including do not exclude things not enumerated that are in the same general class.