Butter. The food product usually known as butter, and which is made exclusively from milk or cream, or both, with or without common salt, with or without additional coloring matter, and containing not less than 80 percent by weight of milkfat, all tolerances having been allowed for.
7 CFR § 58.305
For the purpose of the regulations in this subpart, words in the singular form shall be deemed to impart the plural and vice versa, as the case may demand. Unless the context otherwise requires, the following terms shall have the following meaning.