The Copayment, according to the Centers for Medicare and Medicaid (CMS) is defined as:
In some Medicare health and prescription drug plans, the amount you pay for each medical service, like a doctor’s visit, or prescription. A copayment is usually a set amount you pay. For example, this could be $10 or $20 for a doctor’s visit or prescription. Copayments are also used for some hospital outpatient services in the Original Medicare Plan.
(source: Medicare.gov)
You can review each Medicare plan's cost-sharing details (copayment or co-insurance for all phases of coverage and pharmacy types) by click on the Rx$ icon under the plan name when using our Medicare Advantage Plan Finder or MA-Finder (enter your ZIP to begin) or our stand-alone Medicare Part D Plan Finder or PDP-Finder (choose your state to begin).