Final answer:
The term for the amount of money due from a subscriber to cover a portion of a medical bill is a copayment. This is a fixed amount paid before receiving services, different from a deductible which must be paid before insurance coverage begins.
Step-by-step explanation:
The amount of money due from a subscriber to cover a portion of a medical bill is known as a copayment. A copayment is a fixed amount that an insurance policyholder must pay before receiving medical services. Contrast this with a deductible, which is an amount that insurance policyholders must pay out of their own pocket before the insurance coverage starts to pay.