median umbilical ligamentA fibrous cord that connects the urinary bladder to the umbilicus (navel). The median umbilical ligament is formed as the allantoic stalk during fetal…
mediastinal pleuraThe thin membrane that lines the chest cavity in the area between the lungs.
mediastinoscope(MEE-dee-uh-STIN-oh-skope) A thin, tube-like instrument used to examine the tissues and lymph nodes in the area between the lungs.
mediastinoscopy(MEE-dee-as-tih-NOS-koh-pee) A procedure in which a mediastinoscope is used to examine the organs in the area between the lungs and nearby lymph nodes.
mediastinum(mee-dee-a-STYE-num) The area between the lungs. The organs in this area include the heart and its large blood vessels, the trachea, the esophagus, the…
MedicaidMedicaid is federal government program run by the individual states. It's designed to provide assistance to people who can't afford skilled or custodial…
Medicaid Spend-downA process whereby an individual who meets the Medicaid medical eligibility criteria, but has income that exceeds the financial eligibility ceiling, may…
Medicaid/Medical AssistanceA joint federal-state health insurance program that is run by the states and covers certain low-income people (especially children and pregnant women)…
medical castrationRefers to the use of drugs to suppress the function of the ovaries or testicles.
medical device(MEH-dih-kul dee-VICE) An instrument, tool, machine, test kit, or implant that is used to prevent, diagnose, or treat disease or other conditions.
Medical ErrorAn unintended but preventable adverse effect of care, whether or not it is evident or harmful to the patient.
Medical Loss Ratio (MLR)A basic financial measurement used in the Affordable Care Act to encourage health plans to provide value to enrollees.
medical nutrition therapy(MEH-dih-kul noo-TRIH-shun THAYR-uh-pee) Treatment based on nutrition. It includes checking a person's nutrition status, and giving the right foods or…
Medical Oncologist(MEH-dih-kul on-KAH-loh-jist) A doctor who specializes in diagnosing and treating cancer using chemotherapy, hormonal therapy, and biological therapy.
Medical ProcedureAn examination, surgery, diagnostic test, a laboratory test that is done by a healthcare provider.
Medical RecordDocumentation of a patient's medical history and care.
Medical UnderwritingA process used by insurance companies to try to figure out your health status when you're applying for health insurance coverage to determine whether to…
Medically NecessaryA drug, device, procedure, treatment plan, or other therapy that is covered under your health insurance policy and that your doctor, hospital, or provider…
MedicareMedicare is a federal government insurance program designed to provide healthcare coverage for people 65 or older, certain disabled people, and people…
Medicare AdvantageAn option Medicare beneficiaries can choose to receive most or all of their Medicare benefits through a private insurance company.
Medicare Advantage (Medicare Part C)A type of Medicare health plan offered by a private company that contracts with Medicare to provide you with all your Medicare Part A and Part B benefits.
Medicare Cost PlansMedicare cost plans are a type of HMO that contracts as a Medicare Health Plan.
Medicare Hospital Insurance TaxA tax under the Federal Insurance Contributions Act (FICA) that is a United States payroll tax imposed by the Federal government on both employees and…
Medicare Part DA program that helps pay for prescription drugs for people with Medicare who join a plan that includes Medicare prescription drug coverage.
Medicare Select PlansA type of Medigap policy that may require the Medicare Beneficiary to use hospitals and, in some cases, doctors within its network to be eligible for full…
Medicare Supplement (Medigap) InsurancePrivate insurance policies that can be purchased to "fill-in the gaps" and pay for certain out-of-pocket expenses (like deductibles and coinsurance) not…
medication(MEH-dih-KAY-shun) A legal drug that is used to prevent, treat, or relieve symptoms of a disease or abnormal condition.
Medication GuideA medication guide contains information for patients on how to safely use a drug product.
Medication/MedicineAny substance or substances used in treating disease or illness.
medicine(MEH-dih-sin) Refers to the practices and procedures used for the prevention, treatment, or relief of symptoms of a diseases or abnormal conditions.
medroxyprogesteroneA hormonal anticancer drug that is also used in cancer prevention. It belongs to the family of drugs called progestins.
medroxyprogesterone acetateA drug used to prevent endometrial cancer. It is also used to treat menstrual disorders and as a form of birth control.
medullary breast carcinoma(MED-yoo-LAYR-ee brest KAR-sih-NOH-muh) A rare type of breast cancer that often can be treated successfully.
medullary thyroid cancer(MED-yoo-LAYR-ee THY-royd KAN-ser) Cancer that develops in C cells of the thyroid.
medulloblastoma(MED-yoo-loh-blas-TOH-muh) A malignant brain tumor that begins in the lower part of the brain and that can spread to the spine or to other parts of the…
MefloquineA drug used against malaria for both prevention and treatment.
mega-voltage linear acceleratorA machine that uses electricity to form a stream of fast-moving subatomic particles. This creates high-energy radiation that may be used to treat cancer.
MegaceA drug used to block estrogen and suppress the effects of estrogen and androgens.
megestrolA drug used to block estrogen and suppress the effects of estrogen and androgens.
MeiosisA special form of cell division in which each daughter cell receives half the amount of DNA as the parent cell.
MEK inhibitor AZD6244(... in-HIH-bih-ter...) A substance being studied in the treatment of several types of cancer.
Melan-A proteinA substance found on the surface of melanoma cells. It is being used to develop cancer vaccines that may help the immune system kill cancer cells.
melanin(MEH-luh-nin) A pigment that gives color to skin and eyes and helps protect it from damage by ultraviolet light.
melanocortin 1 receptor(meh-LA-nuh-KOR-tin 1 reh-SEP-ter) A protein found in skin and eye cells that make melanin (a pigment that gives color to the skin and helps protect it…
Melanocyte(mel-AN-o-site) A cell in the skin and eyes that produces and contains the pigment called melanin.
melanoma(MEH-luh-NOH-muh) A form of cancer that begins in melanocytes (cells that make the pigment melanin).
melanoma in situ(MEH-luh-NOH-muh in SY-too) Abnormal melanocytes (cells that make melanin, the pigment that gives skin its color) are found in the epidermis (outer layer…
melanoma vaccineA cancer vaccine prepared from human melanoma cancer cells. It can be used alone or with other therapy in treating melanoma.
melanotropin receptor(meh-LA-nuh-TROH-pin reh-SEP-ter) A protein found in skin and eye cells that make melanin (a pigment that gives color to the skin and helps protect it…
melatonin(MEH-luh-TOH-nun) A hormone made by the pineal gland (tiny organ near the center of the brain).
melphalanA drug that is used to treat multiple myeloma and ovarian epithelial cancer and is being studied in the treatment of other types of cancer.
memantine hydrochloride(MEH-mun-teen HY-droh-KLOR-ide) A drug used to treat dementia caused by Alzheimer disease.
Member Survey ResultsA survey conducted by the Consumer Assessment of Healthcare Providers and Systems (CAHPS) which asks health plan members to rate the care their…
membraneA very thin layer of tissue that covers a surface.
MEN syndrome(... SIN-drome) An inherited condition that may result in the development of cancers of the endocrine system.
MEN-10755An anticancer drug that belongs to the family of drugs called antitumor antibiotics.
MEN1 syndrome(... SIN-drome) A rare, inherited disorder that affects the endocrine glands and can cause tumors in the parathyroid and pituitary glands and the pancreas.
meningeal(meh-NIN-jee-ul) Having to do with the meninges (three thin layers of tissue that cover and protect the brain and spinal cord).
meningeal metastasis(meh-NIN-jee-ul meh-TAS-tuh-sis) Cancer that has spread from where it first formed in the body to the meninges (three thin layers of tissue that cover and…
meninges(meh-NIN-jees) The three thin layers of tissue that cover and protect the brain and spinal cord.
meningioma(meh-NIN-jee-OH-muh) A type of slow-growing tumor that forms in the meninges (thin layers of tissue that cover and protect the brain and spinal cord).
meningitis(meh-nin-JY-tis) Inflammation of the meninges (three thin layers of tissue that cover and protect the brain and spinal cord).
Menopausal(men'o-pawz"ul) describes the time of life when the ovaries stop making estrogen.
menopausal hormone therapy(MEH-nuh-PAW-zul HOR-mone THAYR-uh-pee) Hormones (estrogen, progesterone, or both) given to women after menopause to replace the hormones no longer…
Menopause(MEH-nuh-PAWZ) The time of life when a woman's menstrual periods stop. A woman is in menopause when she hasn't had a period for 12 months in a row.
Menses(men'sees) the monthly flow of blood from the genital tract of women. Also called menstruating or the period.
menstrual cycle(MEN-stroo-al) The monthly cycle of hormonal changes from the beginning of one menstrual period to the beginning of the next.
menstrual period(MEN-stroo-al PEER-ee-od) The periodic discharge of blood and tissue from the uterus.
menstruation(MEN-stroo-AY-shun) Periodic discharge of blood and tissue from the uterus. From puberty until menopause, menstruation occurs about every 28 days when a…
mental healthA person's overall psychological and emotional condition. Good mental health is a state of well-being in which a person is able to cope with everyday…
mental health counselorA specialist who can talk with patients and their families about emotional and personal matters, and can help them make decisions.
meperidine(meh-PAYR-ih-deen) A morphine-like drug used to relieve medium to severe pain. It is a type of opioid analgesic and may be habit-forming.
mercaptopurineA drug used to treat acute lymphatic leukemia. It belongs to the family of drugs called antimetabolites. Also called Purinethol.
mercuryA silver-white, poisonous metal that is a liquid at ordinary temperatures. It is commonly used in thermometers and amalgams, and has been used as an…
mercy killingAn easy or painless death, or the intentional ending of the life of a person suffering from an incurable or painful disease at his or her request.
meridian(meh-RID-ee-un) In traditional Chinese medicine, one of 20 channels that form a network through which qi (the body's vital energy) flows and that connect…
Merkel cell cancer(MER-kel sel KAN-ser) A rare type of cancer that forms on or just beneath the skin, usually in parts of the body that have been exposed to the sun.
MerozoiteA daughter cell formed by asexual development in the life cycle of malaria parasites.
mesenchymalRefers to cells that develop into connective tissue, blood vessels, and lymphatic tissue.
mesenteric membraneThe peritoneal membrane that attaches the intestines to the abdominal wall near the back.
mesnaA drug that helps protect the kidneys and bladder from the toxic effects of anticancer drugs such as ifosfamide and cyclophosphamide.
mesonephromaA rare type of tumor, usually of the female genital tract, in which the insides of the cells look clear when viewed under a microscope.
mesothelin(mez-oh-THEE-lin) A protein found on the surface of certain types of normal cells and cancer cells.
mesothelioma(meh-zuh-thee-lee-OH-muh) A benign (noncancerous) or malignant (cancerous) tumor affecting the lining of the chest or abdomen.
metabolic(MEH-tuh-BAH-lik) Having to do with metabolism (the total of all chemical changes that take place in a cell or an organism to produce energy and basic…
metabolic acidosis(MEH-tuh-BAH-lik A-sih-DOH-sis) A condition in which the blood is too acidic. It may be caused by severe illness or sepsis (bacteria in the bloodstream).
Metabolic Disorder(MEH-tuh-BAH-lik dis-OR-der) A condition in which normal metabolic processes are disrupted, usually because of a missing enzyme.
metabolic therapy(MEH-tuh-BAH-lik THAYR-uh-pee) Treatment to correct changes in metabolism that can be caused by disease.
metabolic type(MEH-tuh-BAH-lik tipe) In alternative medicine, a theory that people fall into one of three groups (protein, carbohydrate, or mixed type) based on the…
metabolism(meh-TA-boh-lih-zum) The total of all chemical changes that take place in a cell or an organism.
metabolite(meh-TA-boh-lite) A substance made or used when the body breaks down food, drugs or chemicals, or its own tissue (for example, fat or muscle tissue).
Metal LevelA metal level, also known as a benefit level, is a group of plans that have similar value. Plan levels include bronze, silver, gold and platinum.
metallic(meh-TA-lik) Having to do with metal. Some cancer treatments may change the sense of taste and cause foods to have a metallic taste.
MetaplasiaA change of cells to a form that does not normally occur in the tissue in which it is found.
metaplastic carcinomaA general term used to describe cancer that begins in cells that have changed into another cell type (for example, a squamous cell of the esophagus…
metastasectomy(meh-TAS-tuh-SEK-toh-mee) Surgery to remove one or more metastases (tumors formed from cells that have spread from the primary tumor).
metastasesWhen cancer spreads to another location in the body. For example, if breast cancer cells spread to the bone, this is called a "breast cancer metastasis."