The following words and phrases when used in this chapter shall have the meanings given to them in this section unless the context clearly indicates otherwise:
"Cooperative purchasing." Procurement conducted by or on behalf of more than one public procurement unit or by a public procurement unit with an external procurement activity.
"External procurement activity." A buying organization not located in this Commonwealth which if located in this Commonwealth would qualify as a public procurement unit. An agency of the United States is an external procurement activity.
"Local public procurement unit." A political subdivision, public authority, educational, health or other institution and, to the extent provided by law, any other entity, including a council of governments or an area government, which expends public funds for the procurement of supplies, services and construction, any nonprofit corporation operating a charitable hospital and any nonprofit fire company, nonprofit rescue company and nonprofit ambulance company.
"Public procurement unit." A local public procurement unit or a purchasing agency.