a fee paid by a subscriber to a service for the use of additional services not covered by the subscription
copayment in American English
(kouˈpeimənt)
noun
a contributory payment by an employer, usually matching that of an employee, toward the payment of health-care or life-insurance premiums, a pension fund, etc
Word origin
[co- + payment]co- is a prefix meaning “with,” “together,” “in association,” sometimes with the derivedsense “auxiliary, subsidiary” (coenzyme; copilot), and, in mathematics and astronomy, with the sense “complement” (codeclination)