In this subchapter, the following definitions apply: (1) Carrier and broker. - The terms "carrier" and "broker" include a receiver or trustee of a carrier and broker, respectively. (2) Association. - The term "association" means an organization maintained by or in the interest of a group of carriers or brokers providing transportation or service subject to jurisdiction under chapter 135 that performs a service, or engages in activities, related to transportation under this part.