California Code, Financial Code - FIN § 110000

(a) “Ammunition” has the same meaning as provided in subdivision (b) of Section 16150 of the Penal Code.

(b) “Firearm” has the same meaning as provided in subdivisions (a) and (b) of Section 16520 of the Penal Code.

(c) “Firearm accessory” means an attachment or device designed or adapted to be inserted into, affixed onto, or used in conjunction with a firearm that is designed, intended, or functions to alter or enhance the firing capabilities of a firearm, the lethality of the firearm, or a shooter's ability to hold and use a firearm.

(d) “Firearms merchant” means a business licensed in California as a firearms dealer or ammunition vendor for which the highest sales value is, or is expected to be, from the combined sale in California of firearms, firearm accessories, or ammunition, as stated by the business to its merchant acquirer in the ordinary course of business.

(e) “Merchant acquirer” means an entity that establishes a relationship with a merchant for the purposes of processing credit, debit, or prepaid transactions.

(f) “Payment card network” means an entity that provides services that route transactions between bank participants to conduct debit, credit, or prepaid transactions for the purpose of authorization, clearance, or settlement.