Registrant. This term means: a commodity pool operator; commodity trading advisor; futures commission merchant; introducing broker; leverage transaction merchant; floor broker; floor trader; major swap participant; retail foreign exchange dealer; or swap dealer that is subject to these regulations; or an associated person of any of the foregoing other than an associated person of a swap dealer or major swap participant.
17 CFR § 1.3
Words used in the singular form in the rules and regulations in this chapter shall be deemed to import the plural and vice versa, as the context may require. The following terms, as used in the Commodity Exchange Act, or in the rules and regulations in this chapter, shall have the meanings hereby assigned to them, unless the context otherwise requires: