Allowed Amount:
Maximum amount on which payment is based for covered health care services. This may be called "eligible expence", "payment allowance", or "negotiated rate". 

Co-Insurance:
Your share of the costs of a covered health care service, calculated as a percent (for example, 20%) of the allowed amount for the service. You may pay co-insurance PLUS any deductibles you owe.

Deductible:
The amount you owe for health care services before your insurance will begin to pay. For example, you have a $1000 deductible. Your insurance will not pay anything until you have satisfied this amount. The deductible may not apply to all services. 

Co-payment:
A fixed amount (for example $20) you pay for a covered health care service and is typically collected at the time of service. The amount can vary by the type of service being rendered.

Out of pocket limit:
The most you pay during a policy period (typically calendar year but not always) before your insurance plan will pay 100% of the allowed amount. This limit never includes your premium. Some insurances do not count all of your copayments, deductibles and co-insurances towards this amount.