Medicare Glossary

Health Maintenance Organization (HMO)

A type of Medicare Advantage plan where you generally must use doctors, hospitals, and other providers in the plan's network, except in emergencies. You typically need a referral to see a specialist.

Also known as: HMO

Medicare Cost Plan

A type of Medicare health plan, less common than Medicare Advantage, in which members can use plan providers for lower cost-sharing or go outside the network and have services covered under Original Medicare instead.

Also known as: Cost Plan

Preferred Provider Organization (PPO)

A type of Medicare Advantage plan that allows you to see any provider who accepts Medicare, but you pay less when you use the plan's preferred (in-network) providers. Unlike HMOs, PPOs generally do not require referrals for specialists.

Also known as: PPO

Service Area

The geographic area where a Medicare Advantage or Part D plan is available and provides coverage. Plans may have different networks and costs in different parts of their service area. Moving outside a plan's service area may trigger a Special Enrollment Period.