RCW 82.45.020: "Seller" defined.

As used in this chapter the term "seller," unless otherwise indicated by the context, shall mean any individual, receiver, assignee, trustee in bankruptcy, trust, estate, firm, copartnership, joint venture, club, company, joint stock company, business trust, municipal corporation, quasi municipal corporation, corporation, association, society, or any group of individuals acting as a unit, whether mutual, cooperative, fraternal, nonprofit or otherwise; but it shall not include the United States or the state of Washington.