As used in this act:

(a) “Health maintenance organization” means that term as defined in section 3501.

(b) “Insurer” means an individual, corporation, association, partnership, reciprocal exchange, inter-insurer, Lloyds organization, fraternal benefit society, or other legal entity, engaged or attempting to engage in the business of making insurance or surety contracts. Except as otherwise provided in section 3503 and unless the context requires otherwise, insurer includes a health maintenance organization.