Glossary of medical specialties and healthcare terms

Last updated: October 5, 2026 · Reviewed by the PickTheDoc.com team · Editorial policy

Specialty names come mostly from Greek and Latin, which is why they rarely tell you what the doctor actually does. This glossary translates them into plain language, along with the insurance and healthcare terms that come up when booking an appointment.

Specialties we cover in detail

Each of these links to a full guide explaining what the specialty treats and when to see one.

Cardiologist: A doctor who treats the heart and blood vessels, including chest pain, palpitations, high blood pressure, and heart failure.
Dermatologist: A doctor who treats the skin, hair, and nails, including rashes, acne, eczema, hair loss, and skin cancer screening.
ENT (Otolaryngologist): A doctor who treats the ears, nose, throat, and sinuses. The full name is otolaryngologist, but almost everyone says ENT.
Gastroenterologist: A doctor who treats the digestive system, including the esophagus, stomach, intestines, liver, gallbladder, and pancreas.
Neurologist: A doctor who treats the brain, spinal cord, and nerves, including migraine, seizures, numbness, tremor, and memory problems.
OB-GYN: An obstetrician-gynecologist. Obstetrics covers pregnancy and childbirth; gynecology covers the female reproductive system.
Ophthalmologist: A medical eye doctor who can prescribe medication and perform eye surgery. Distinct from an optometrist.
Orthopedist: A doctor who treats bones, joints, muscles, tendons, and ligaments. Also called an orthopedic surgeon, though most care is non-surgical.
Primary Care Physician (PCP): A generalist who treats everyday illness, manages chronic conditions, provides preventive care, and refers to specialists when needed.
Psychiatrist: A medical doctor specializing in mental health who can diagnose conditions and prescribe medication.
Pulmonologist: A doctor who treats the lungs and breathing, including asthma, COPD, chronic cough, and sleep-related breathing disorders.
Urologist: A doctor who treats the urinary tract in all patients and the male reproductive system.

Other specialties and clinical roles

You may be referred to these, though we do not yet have dedicated guides for them.

Allergist / Immunologist: Treats allergies, asthma, and immune system disorders.
Anesthesiologist: Manages sedation, pain control, and monitoring during surgery.
Endocrinologist: Treats hormone-related conditions, including diabetes and thyroid disorders.
Geriatrician: A physician specializing in the care of older adults.
Hematologist: Treats blood disorders such as anemia and clotting problems.
Hospitalist: A physician who cares for patients specifically during a hospital stay.
Nephrologist: Treats kidney disease and manages dialysis.
Nurse Practitioner (NP): An advanced practice nurse who can diagnose, treat, and in most states prescribe medication. Interested in this role as a career? Explore the Nurse Practitioners career profile on JobShift Atlas (opens in a new tab, affiliated site).
Oncologist: Treats cancer, including chemotherapy and other systemic therapies.
Optometrist: Examines eyes and prescribes glasses and contact lenses. Not a medical doctor; see an ophthalmologist for eye disease.
Pediatrician: A primary care physician for infants, children, and adolescents.
Physician Assistant (PA): A licensed clinician who diagnoses and treats patients while working with a supervising physician. Interested in this role as a career? Explore the Physician Assistants career profile on JobShift Atlas (opens in a new tab, affiliated site).
Physiatrist: Specializes in physical medicine and rehabilitation, focusing on restoring function after injury or illness.
Podiatrist: Treats conditions of the foot and ankle.
Psychologist: Provides talk therapy and psychological testing. Generally does not prescribe medication.
Radiologist: Interprets imaging such as X-rays, CT scans, and MRIs. You usually do not meet them directly.
Rheumatologist: Treats inflammatory and autoimmune conditions affecting joints and connective tissue, such as rheumatoid arthritis and lupus.

Healthcare and insurance terms

Acute: A symptom or condition that starts suddenly and is usually short-lived. The opposite of chronic.
Allowed amount: The maximum amount a health plan recognizes for a covered service. What you owe depends on the plan's deductible, copay, coinsurance, network rules, and other terms.
Appeal: A formal request for a health plan or program to review a decision, such as a denial of coverage or payment.
Balance billing: When a provider bills you for the difference between its charge and the amount recognized by your plan. This is usually associated with out-of-network care, and federal or state protections may limit it in some situations.
Claim: A request submitted to a health plan for payment or reimbursement for healthcare items or services.
Chronic: A condition lasting a long time, generally three months or more, often managed rather than cured.
Coinsurance: The percentage of the allowed amount you pay for a covered service, such as 20%. A deductible may also apply.
Copay: A fixed amount you pay for a covered service. Specialist copays are typically higher than primary care copays.
Cost sharing: Your share of the cost of covered care, commonly including deductibles, copays, and coinsurance. It generally does not include premiums or non-covered services.
Covered service: A healthcare item or service that a plan includes in its benefits, subject to the plan's eligibility, medical-necessity, network, and authorization rules.
Deductible: The amount you pay out of pocket each year before insurance begins covering costs.
Differential diagnosis: The list of possible causes a doctor considers before narrowing down to a single explanation.
Emergency care: Immediate evaluation and care for a serious or potentially life-threatening condition. If you believe you are experiencing an emergency, call 911.
Evidence of Coverage (EOC): A detailed plan document explaining covered benefits, costs, rules, and member rights. Medicare health and drug plans provide an Evidence of Coverage for each plan year.
Explanation of Benefits (EOB): A statement showing how a health plan processed a claim, including provider charges, allowed amounts, plan payments, and the amount listed as your responsibility. An EOB is not a bill.
Formulary: A health plan's list of covered prescription drugs. Coverage tiers and requirements such as prior authorization or step therapy may also be listed.
Health Maintenance Organization (HMO): A type of health plan that generally uses a defined provider network. Many HMOs require members to choose a primary care provider and get referrals for some specialist care, but exact rules vary.
In-network: A provider who has an agreement with your insurance plan, usually meaning lower cost to you.
Medically necessary: A plan term for care that meets its standards for coverage based on the condition and accepted clinical practice. Definitions and review processes vary by plan.
Open Enrollment: A set period when eligible people can enroll in or change health coverage. Dates and permitted changes depend on the insurance program or plan.
Out-of-network: A provider or facility that does not have a contract with your specific health plan. Non-emergency care may cost more or may not be covered, depending on the plan.
Out-of-pocket maximum: The most you pay during a plan year for your share of covered, in-network services before the plan generally pays the full allowed amount. Premiums, non-covered care, and some other charges usually do not count toward it.
Preferred Provider Organization (PPO): A type of health plan with a preferred provider network that may also cover out-of-network care at a higher cost. Referral requirements and other rules depend on the plan.
Premium: The amount paid regularly to keep health coverage active, whether or not you use healthcare services.
Prior authorization: Approval your insurer requires before covering certain tests, procedures, or medications.
Provider: A person or organization that delivers healthcare, such as a doctor, nurse practitioner, therapist, hospital, clinic, or laboratory.
Provider directory: A plan's list of participating doctors, facilities, and other providers. Confirm current network status with both the plan and the provider before receiving non-emergency care.
Referral: A recommendation from one doctor to another, often required by insurance before a specialist visit is covered.
Second opinion: An evaluation by another qualified clinician who reviews a diagnosis, recommendation, or proposed care plan. Coverage and referral requirements vary.
Service area: The geographic area where a health plan accepts members and provides access to its network, subject to the plan's rules.
Step therapy: A prescription-coverage rule that may require trying a plan-preferred drug before the plan covers another drug. Plans have processes for coverage decisions and exceptions.
Summary of Benefits and Coverage (SBC): A standardized summary that helps people compare a health plan's benefits, cost sharing, exclusions, and coverage examples. The full plan documents contain more detail.
Triage: The process of sorting patients by urgency so the most time-critical cases are treated first.
Urgent care: A walk-in clinic for problems that need same-day attention but are not life-threatening.
Walk-in clinic: A clinic that accepts patients without a scheduled appointment, usually for routine or minor health concerns rather than emergencies.

Sources

This is not medical advice. These definitions are educational only and do not diagnose conditions. In an emergency, call 911. Read our full medical disclaimer.

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