What are the entities of medical billing?

Some of the entities are:

Payers - these are the insurance companies who actually pay the bills for medical services provided

Providers - This includes doctors, hospitals, labs, pharmacies, anyone involved in providing a product or service

Patients - Pretty much what it sounds like. The person receiving the product/service

Subscriber - The person who is the primary 'Insured party', can differ from the patient. Usually an employee who is insured and covering themself and other familiy members

Dependent - An insured person other than the subscriber, usually a spouse or child of the subscriber.

Enrollee or Member - I've seen both of these terms used with the same meaning, which is any insured person. Basically a combination of the 'Subscriber' and 'Dependent' groups.

Sponsor - This is the entity that offers insurance coverage to individuals, often an employer or a membershiop organization