For the purposes of this chapter:

(1) "Department" means the department of agriculture of the state of Washington;

(2) "Director" means the director of the department or the director's duly appointed representative;

(3) "Person" means a natural person, individual, firm, partnership, corporation, company, society, and association, and every officer, agent, or employee thereof. This term shall import either the singular or plural as the case may be;

(4) "Market" or "marketing area" means any geographical area within the state or another state comprising one or more counties or parts thereof, where marketing conditions are substantially similar and which may be designated by the director as one marketing area;

(5) "Milk" means all fluid milk from cows as defined in chapter 15.36 RCW and rules adopted under chapter 15.36 RCW;

(6) "Milk products" includes any product manufactured from milk or any derivative or product of milk;

(7) "Milk dealer" means any person engaged in the handling of milk in his or her capacity as the operator of a milk plant, as that term is defined in chapter 15.36 RCW and rules adopted under chapter 15.36 RCW:

(a) Who receives milk in an unprocessed state from dairy farms, and who processes milk into milk or milk products; and

(b) Whose milk plant is located within the state or from whose milk plant milk or milk products that are produced at least in part from milk from producers are disposed of to any place or establishment within a marketing area;

(8) "Producer" means a person producing milk within this state for sale under a grade A milk permit issued by the department under the provisions of chapter 15.36 RCW or, if the director so provides by rule, a person who markets to a milk dealer milk produced under a grade A permit issued by another state;

(9) "Classification" means the classification of milk into classes according to its utilization by the department;

(10) The terms "plan," "market area and pooling arrangement," "market area pooling plan," "market area and pooling plan," "market pool," and "market plan" all have the same meaning;

(11) "Producer-dealer" means a producer who engages in the production of milk and also operates a plant from which an average of more than three hundred pounds daily of milk products, except filled milk, is sold within the marketing area and who has been so designated by the director. A state institution which processes and distributes milk of its own production shall be considered a producer-dealer for purposes of this chapter, but the director may by rule exempt such state institutions from any of the requirements otherwise applicable to producer-dealers.