Section 1. The following words as used in this chapter shall have the following meanings unless the context otherwise requires: ''Commissioner'', the commissioner of agricultural resources. ''Department'', the department of agricultural resources. ''Director'', in sections 16 to 31A, inclusive, the director of the division of regulatory services in the department of agricultural resources. ''Inspector'', in sections thirty-two to thirty-eight, inclusive, the inspector of apiaries. ''Nursery stock'', trees, shrubs, woody plants and strawberry plants, whether wild or cultivated, and parts thereof for propagation. ''Riding school operator'', any person owning or having the custody of one or more horses which are let for hire to be ridden or driven, with or without the furnishing of riding or driving instructions. ''Trustees'', the trustees for county cooperative extension service.