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Medical Billing Glossary — 100 Terms Every Biller Should Know

March 31, 2026

Medical billing involves many technical terms related to insurance claims, coding, reimbursements, and healthcare payment processes. For billers, coders, and healthcare administrators, understanding these terms is essential to ensure accurate claim submission, reduced denials, and faster reimbursements.

This medical billing glossary includes 100 essential medical billing terms and definitions that every biller, coder, and healthcare professional should understand. Whether you’re new to healthcare billing or want a quick reference guide, this glossary will help simplify the complex language of medical billing.

What Is Medical Billing Terminology?

Medical billing terminology refers to the standardized language used in healthcare billing and insurance claims processing. These terms describe processes such as claim submission, coding, insurance verification, reimbursement, and patient billing.

Understanding medical billing terminology helps healthcare organizations maintain accurate documentation, proper coding, and efficient revenue cycle management.

Why Understanding Medical Billing Terms Is Important

Learning medical billing terms is important for several reasons:

  • Helps reduce claim denials and rejections

  • Improves billing accuracy and compliance

  • Supports proper CPT and ICD-10 coding

  • Helps practices maximize insurance reimbursements

  • Enhances revenue cycle management efficiency

Here are the Complete Medical Billing Glossary (A–Z) Listed Below:

A

1. Accounts Receivable (AR)

The total amount of money owed to a healthcare provider by patients or insurance companies for services already provided.

2. Allowed Amount

The maximum amount an insurance company agrees to pay for a specific medical service.

3. Assignment of Benefits (AOB)

A patient authorization that allows the insurance company to pay the healthcare provider directly.

4. Advance Beneficiary Notice (ABN)

A written notice given to Medicare patients informing them that a service may not be covered and they might have to pay out of pocket.

5. Account Number

A unique identifier assigned to a patient’s billing record.

B

6. Balance Billing

Charging a patient for the difference between the provider’s charge and the amount paid by insurance.

7. Billing Cycle

The period between billing statements sent to patients.

8. Billable Charge

The amount billed by a healthcare provider for services rendered.

9. Bundling

The practice of combining multiple services into a single billing code according to payer guidelines.

10. Benefit Period

The timeframe during which insurance benefits apply.

C

11. Claim

A request submitted to an insurance company asking for payment for healthcare services provided.

12. Claim Adjustment

A correction or modification made to a claim after it has been submitted.

13. Clean Claim

A claim that contains no errors or missing information, allowing it to be processed quickly.

14. Copayment (Copay)

A fixed amount a patient pays for healthcare services at the time of service.

15. Coinsurance

The percentage of medical costs a patient must pay after the deductible is met.

16. CPT (Current Procedural Terminology)

A standardized coding system used to describe medical procedures and services.

17. Coordination of Benefits (COB)

The process of determining which insurance policy pays first when a patient has multiple insurance plans.

18. Clearinghouse

A third-party service that reviews and forwards electronic claims to insurance companies.

D

19. Deductible

The amount a patient must pay out of pocket before insurance coverage begins.

20. Denial

A rejection of a claim by an insurance company due to errors, missing information, or non-covered services.

21. Diagnosis Code

A code that describes a patient’s medical condition, usually using ICD-10.

22. Date of Service (DOS)

The date when medical treatment was provided.

23. Downcoding

When an insurance company reduces the service code to a lower-paying code.

24. DRG (Diagnosis Related Group)

A system used to categorize hospital cases for reimbursement purposes.

E

25. EOB (Explanation of Benefits)

A document sent by the insurance company explaining how a claim was processed.

26. Eligibility Verification

The process of confirming a patient’s insurance coverage before providing services.

27. Electronic Claim

A claim submitted electronically through billing software or clearinghouses.

28. Encounter Form

A form used by healthcare providers to record diagnoses and procedures during a patient visit.

29. Effective Date

The date when an insurance policy becomes active.

F

30. Fee Schedule

A list of standard charges for medical services.

31. Financial Responsibility

The portion of medical expenses that the patient must pay.

32. Fraud

Intentional misrepresentation or billing for services not provided.

33. Filing Limit

The deadline for submitting claims to insurance companies.

34. Follow-Up

The process of checking the status of submitted claims and resolving payment delays.

G

35. Guarantor

The person financially responsible for paying the patient’s medical bill.

36. Group Number

A number identifying a specific employer-sponsored insurance plan.

37. Global Period

A timeframe in which related services are included in the original procedure payment.

H

38. HCPCS (Healthcare Common Procedure Coding System)

A coding system used to report medical services, procedures, and equipment.

39. HIPAA (Health Insurance Portability and Accountability Act)

A federal law that protects patient health information and privacy.

40. HMO (Health Maintenance Organization)

A type of insurance plan requiring patients to use network providers.

I

41. ICD-10

International Classification of Diseases used to code diagnoses and medical conditions.

42. In-Network Provider

A healthcare provider who has a contract with an insurance company.

43. Insurance Verification

The process of confirming patient insurance details before treatment.

44. Itemized Bill

A detailed statement listing each service provided and its associated cost.

J

45. Justification

Documentation that supports the medical necessity of a service.

K

46. Key Performance Indicators (KPIs)

Metrics used to evaluate billing and revenue cycle performance.

L

47. Ledger

A financial record of patient charges, payments, and adjustments.

48. Liability

The legal responsibility for paying healthcare expenses.

49. Late Charge

A fee applied when payments are not made by the due date.

M

50. Medical Necessity

A service or procedure that is required for diagnosis or treatment.

51. Modifier

A two-character code added to CPT or HCPCS codes to provide extra information.

52. Managed Care

A healthcare system designed to reduce costs while maintaining quality care.

53. Medical Billing

The process of submitting claims and following up with insurers for reimbursement.

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54. Medical Coding

The process of translating medical services into standardized codes.

N

55. National Provider Identifier (NPI)

A unique identification number assigned to healthcare providers.

56. Non-Covered Service

A service not paid for by an insurance company.

57. Network Provider

A provider contracted with an insurance company.

O

58. Out-of-Pocket Cost

Expenses a patient must pay themselves.

59. Out-of-Network Provider

A provider who does not have a contract with a specific insurance plan.

60. Overpayment

Payment that exceeds the amount owed for a service.

P

61. Patient Responsibility

The portion of medical costs the patient must pay.

62. Prior Authorization

Approval from an insurance company before certain services are performed.

63. Payer

An entity such as an insurance company responsible for paying claims.

64. Practice Management Software

Software used by healthcare providers to manage billing, scheduling, and patient records.

65. PPO (Preferred Provider Organization)

A type of insurance plan allowing patients to see providers both in and out of network.

Q

66. Quality Reporting

Programs that measure healthcare provider performance.

R

67. Reimbursement

Payment made by insurance companies to healthcare providers.

68. Revenue Cycle Management (RCM)

The process of managing financial transactions from patient registration to final payment.

69. Remittance Advice (RA)

A document explaining how a payer processed a claim.

70. Resubmission

Submitting a claim again after correcting errors or missing information.

S

71. Superbill

A document listing services provided during a patient visit used for billing.

72. Statement

A billing notice sent to patients showing their outstanding balance.

73. Secondary Insurance

Additional insurance that covers costs not paid by the primary insurer.

74. Subscriber

The person who holds the insurance policy.

75. Self-Pay

A patient who pays medical expenses without insurance.

T

76. Third-Party Payer

An organization such as an insurance company that pays healthcare claims.

77. Timely Filing

The requirement that claims must be submitted within a specific timeframe.

78. Treatment Authorization

Permission required from an insurer before certain treatments are provided.

U

79. Upcoding

Billing for a more expensive service than the one actually provided.

80. Usual, Customary, and Reasonable (UCR)

The standard amount insurers consider appropriate for a service.

V

81. Verification of Benefits (VOB)

Confirming a patient’s insurance coverage, benefits, and limitations.

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82. Value-Based Care

A healthcare model that rewards providers for quality of care rather than quantity of services.

W

83. Write-Off

The portion of a charge that a provider agrees not to collect.

84. Workers’ Compensation

Insurance that covers medical costs for work-related injuries.

X

85. X-Ray Claim

A billing claim specifically for diagnostic imaging services.

Y

86. Year-to-Date Deductible

The total deductible amount a patient has paid during the year.

Z

87. Zero Balance

An account status indicating no remaining balance is owed.

Additional Important Terms

88. Aging Report

A report showing outstanding claims grouped by how long they have been unpaid.

89. Charge Entry

The process of entering service charges into the billing system.

90. Claim Scrubbing

Reviewing claims for errors before submission.

91. Credentialing

The process of verifying provider qualifications for insurance participation.

92. Duplicate Claim

A claim submitted more than once for the same service.

93. Electronic Remittance Advice (ERA)

An electronic version of remittance advice.

94. Payment Posting

Recording payments received from insurers or patients.

95. Rejection

A claim returned before processing due to incorrect information.

96. Underpayment

When an insurance company pays less than the allowed amount.

97. Write-Up

An adjustment that increases the billed amount.

98. Patient Portal

An online platform allowing patients to view bills and medical records.

99. Authorization Number

A unique number assigned to approved services.

100. Charge Capture

The process of recording billable services to ensure proper reimbursement.

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Medical billing processes can be complex, and small errors in coding or documentation can lead to delayed payments or claim denials. Our experts review your billing workflow to identify opportunities to improve coding accuracy, claim submission, and reimbursement performance.

Submit the form to request a free practice audit and learn how to optimize your medical billing process.

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