Filed. Subject to the provisions of 70.305 and 70.306 of this chapter, a claim for drawback or other document or payment submitted under this part is generally considered to have been filed when it is received by the office of the proper Government official; but if an item is mailed timely with postage prepaid, then the United States postmark date is treated as the date of filing.
27 CFR § 17.11
As used in this part, unless the context otherwise requires, terms have the meanings given in this section. Words in the plural form include the singular, and vice versa, and words indicating the masculine gender include the feminine. The terms includes and including do not exclude things not listed which are in the same general class.