29 CFR 780.1010: Principally.

The exemption is intended to apply to the making of an evergreen wreath. Such a wreath is one made “principally” of evergreens. Principally means chiefly, in the main or mainly (Hartford Accident and Indemnity Co. v. Casualty Underwriters Insurance Co., 130 F. Supp. 56). A wreath is made “principally” of evergreens when it is comprised mostly of evergreens. For example, where a wreath is composed of evergreens and other kinds of material, the evergreens should comprise a greater part of the wreath than all the other materials together, including materials such as frames, stands, and wires. The principal portion of a wreath may consist of any one or any combination of the evergreens listed in section 13(d), including “other evergreens.” The making of wreaths in which natural evergreens are a secondary component is not exempt.