(a) The term credit account shall mean an account which is established by a retail seller under a retail instalment credit agreement as defined under subdivision 8 of section 401 of the Personal Property Law and as provided by section 413 of the Personal Property Law.

(b) The term creditor shall mean a retail seller, except that the term shall also mean a sales finance company which has purchased or acquired the credit accounts of a retail seller in the case where, by contractual agreement between the retail seller and the sales finance company, the sales finance company undertakes on behalf of the retail seller to meet the specific requirements imposed by this Part on a “creditor.”

(c) The term rate shall mean the rate of service charge charged on a credit account.

(d) The term retail seller shall have the meaning assigned to it under subdivision 3 of section 401 of the Personal Property Law.

(e) The term sales finance company shall have the meaning assigned to it under sections 491 and 492(1) of the Banking Law, and applies to a person or company which purchases or acquires credit accounts established by retail sellers, provided that for purposes of this Part the term also includes a bank, trust company, savings bank or savings and loan association which purchases credit accounts established by retail sellers.