Container. Any can, bottle, box, cask, keg, or other closed receptacle, in any size or material, which is for use in the sale of distilled spirits at retail. See subpart K of this part for rules regarding authorized standards of fill for containers.
27 CFR § 5.1
When used in this part and on forms prescribed under this part, the following terms have the meaning assigned to them in this section, unless the terms appear in a context that requires a different meaning. Any other term defined in the Federal Alcohol Administration Act (FAA Act) and used in this part has the same meaning assigned to it by the FAA Act.