Distilling. The conduct by any person of operations that constitute, as defined by 26 U.S.C. 5002, operations as a distiller. Such operations include: The original manufacture of distilled spirits from mash, wort, or wash, or any materials suitable for the production of spirits; (b) the redistillation of spirits in the course of original manufacture; (c) the redistillation of spirits, or products containing spirits; (d) the distillation, redistillation, or recovery of spirits, denatured spirits, or articles containing spirits or denatured spirits; and (e) the redistillation or recovery of tax-free spirits.
27 CFR § 29.45
When used in this subpart and in the forms prescribed under this subpart, where not otherwise distinctly expressed or manifestly incompatible with the intent thereof, terms shall have the meaning ascribed in this section. Words in the plural form shall include the singular, and vice versa, and words in the masculine shall include the feminine. The terms includes and including do not exclude things not enumerated which are in the same general class.