ophthalmoscope(off-THAL-mo-skope) A lighted instrument used to examine the inside of the eye, including the retina and the optic nerve.
opiateA drug used to treat pain. It contains opium or a substance made from opium (such as morphine).
Opioid(OH-pee-OYD) A drug used to treat moderate to severe pain. Opioids are similar to opiates such as morphine and codeine, but they do not contain and are…
opioid growth factor(OH-pee-OYD grohth FAK-ter) A substance made by the body and in the laboratory. It is being studied in the treatment of cancer.
opportunistic infectionAn infection caused by an organism that does not normally cause disease. Opportunistic infections occur in people with weakened immune systems.
oprelvekin(oh-PREL-vuh-KIN) A drug used to increase the number of blood cells, especially platelets, in some cancer patients receiving chemotherapy.
OPT-80A substance being studied in the treatment of diarrhea caused by infection with Clostridium difficile (a type of bacteria that can grow without oxygen) in…
optic nerveThe nerve that carries messages from the retina to the brain.
optic pathway glioma(...glee-OH-muh) A rare, slow-growing tumor that usually forms in the optic nerve, optic chiasm, or optic tract.
oral cancer(OR-ul KAN-ser) Cancer that forms in tissues of the lip or mouth. This includes the front two thirds of the tongue, the upper and lower gums, the lining…
oral contraceptive pill(OR-ul KON-truh-SEP-tiv) A pill used to prevent pregnancy. It contains hormones that block the release of eggs from the ovaries.
Oral Hypoglycemic Agents(First and Second generation Sulfonylureas; Biguanides) Usage by Type II diabetics to lower blood glucose, but they are not insulin pills .
oral surgeonA dentist with special training in surgery of the mouth and jaw.
orchidectomy(or-kih-DEK-toh-mee) Surgery to remove one or both testicles. Also called orchiectomy.
orchiectomy(or-kee-EK-toh-mee) Surgery to remove one or both testicles. Also called orchidectomy.
oregovomab(oh-reh-GOH-voh-mab) A monoclonal antibody that is being studied in the treatment of ovarian cancer.
organA part of the body that performs a specific function. For example, the heart is an organ.
organelle(OR-guh-NEL) A small structure in a cell that is surrounded by a membrane and has a specific function.
organic food(or-GA-nik â¦) Food produced without the use of man-made fertilizer, drugs that increase growth, or drugs that kill insects, bacteria, or other…
organismA living thing, such as an animal, a plant, a bacterium, or a fungus.
orgasm(OR-ga-zum) The final part of the sex act, which involves contraction of sexual organs and a sudden release of endorphins, leading to a feeling of…
Oriental medicine(OR-ee-EN-tul MEH-dih-sin) A medical system that has been used for thousands of years to prevent, diagnose, and treat disease.
Original MedicareOriginal Medicare is fee-for-service coverage under which the government pays your health care providers directly for your Part A (Hospital Insurance)…
oropharyngeal cancer(or-oh-fuh-RIN-jee-ul KAN-ser) Cancer that forms in tissues of the oropharynx (the part of the throat at the back of the mouth, including the soft palate…
oropharynx(or-o-FAIR-inks) The part of the throat at the back of the mouth. It includes the soft palate, the base of the tongue, and the tonsils.
orthodox medicine(OR-thuh-DOX MEH-dih-sin) A system in which medical doctors and other healthcare professionals (such as nurses, pharmacists, and therapists) treat…
orthotopic(OR-thoh-TOP-ik) In medicine, refers to something that occurs in the normal or usual place in the body.
OSI-774A drug used to treat certain types of non-small cell lung cancer. It is also used together with gemcitabine to treat pancreatic cancer and is being…
OSI-7904LA substance that is being studied in the treatment of cancer. It belongs to the family of drugs called thymidylate synthase inhibitors.
osmolalityThe concentration of particles dissolved in a fluid. The osmolality of serum can help diagnose several medical conditions such as dehydration, diabetes…
osmotic(oz-MAH-tik) Having to do with osmosis (the passage of a liquid through a membrane from a less concentrated solution to a more concentrated one).
osteitis deformans(OS-tee-I-tis dih-FOR-manz) A chronic condition in which both the breakdown and regrowth of bone are increased.
osteogenic sarcoma(OS-tee-oh-JEH-nik sar-KOH-muh) A cancer of the bone that usually affects the large bones of the arm or leg.
osteolytic(OS-tee-oh-LIH-tik) Causing the breakdown of bone.
osteomyelitis(OS-tee-oh-MY-uh-LY-tis) Inflammation of the bone caused by an infection, which may spread to the bone marrow and tissues near the bone.
osteopenia(OS-tee-oh-PEE-nee-uh) A lower-than-normal bone mass or bone mineral density (the amount of bone mineral contained in a certain amount of bone).
Osteoporosis(OS-tee-oh-puh-ROH-sis) A condition that is marked by a decrease in bone mass and density, causing bones to become fragile.
osteosarcoma(OS-tee-oh-sar-KOH-muh) A cancer of the bone that usually affects the large bones of the arm or leg.
ostomy(OS-toh-mee) An operation to create an opening (a stoma) from an area inside the body to the outside. Colostomy and urostomy are types of ostomies.
OTCA medicine that can be bought without a prescription (doctor's order). Examples include analgesics (pain relievers) such as aspirin and acetaminophen.
otolaryngologist(OH-toh-LA-rin-GAH-loh-jist) A doctor who specializes in treating diseases of the ear, nose, and throat. Also called ENT doctor.
ounceA measure of weight (one-sixteenth pound) and volume (one-eighth cup).
Out-of-Network Co-InsuranceThe percent (for example, 40%) you pay of the allowed amount for covered health care services to providers who do not contract with your health insurance…
Out-of-Network Co-PaymentA fixed amount (for example, $30) you pay for covered health care services from providers who do not contract with your health insurance or plan.
Out-of-Network CoinsuranceThe percentage (for example, 40%) you pay of the allowed amount for covered health care services to providers who don't contract with your health…
Out-of-Network CopaymentA fixed amount (for example, $30) you pay for covered health care services from providers who don't contract with your health insurance or plan.
Out-of-network providerFor health plans that utilize an HMO or PPO, a health care provider (such as a hospital or doctor) that is not contracted to be part of the HMO or PPO…
Out-of-PocketThe amount of money you pay for medical services after insurance has paid its contribution.
Out-of-Pocket CostsYour expenses for medical care that aren't reimbursed by insurance. Out-of-pocket costs include deductibles, coinsurance, and copayments for covered…
Out-of-Pocket EstimateAn estimate of the amount that you may have to pay on your own for health care or prescription drug costs.
Out-of-Pocket LimitThe most you pay during a policy period (usually a year) before your health insurance or plan begins to pay 100% of the allowed amount.
Out-of-Pocket MaximumThe most you will have to pay in a year for deductibles and coinsurance for covered benefits.
Out-of-pocket maximum/limitThe most you pay during a policy period (usually one year) before your health insurance or plan starts to pay 100% for covered essential health benefits.
outcomeA specific result or effect that can be measured. Examples of outcomes include decreased pain, reduced tumor size, and improvement of disease.
outpatientA patient who visits a health care facility for diagnosis or treatment without spending the night. Sometimes called a day patient.
Outpatient SurgeryA surgical procedure in which the patient is not required to stay overnight in a hospital.
OvaRex(OH-vuh-REX) A monoclonal antibody that is being studied in the treatment of ovarian cancer.
Ovarian(oh-VAYR-ee-un) Having to do with the ovaries, the female reproductive glands in which the ova (eggs) are formed.
ovarian ablation(oh-VAYR-ee-un a-BLAY-shun) Surgery, radiation therapy, or a drug treatment to stop the functioning of the ovaries. Also called ovarian suppression.
ovarian borderline malignant tumor(oh-VAYR-ee-un...muh-LIG-nunt poh-TEN-shul TOO-mer) A condition in which cells that may become cancer form in the thin layer of tissue that covers an…
ovarian cancer(oh-VAYR-ee-un KAN-ser) Cancer that forms in tissues of the ovary (one of a pair of female reproductive glands in which the ova, or eggs, are formed).
ovarian epithelial cancer(oh-VAYR-ee-un eh-pih-THEE-lee-ul KAN-ser) Cancer that occurs in the cells on the surface of the ovary. Also called epithelial ovarian cancer.
ovarian germ cell tumor(oh-VAYR-ee-un jerm sel TOO-mer) An abnormal mass of tissue that forms in germ (egg) cells in the ovary (female reproductive gland in which the eggs are…
ovarian low malignant potential tumor(oh-VAYR-ee-un...muh-LIG-nunt poh-TEN-shul TOO-mer) A condition in which cells that may become cancer form in the thin layer of tissue that covers an…
ovarian suppression(oh-VAYR-ee-un suh-PREH-shun) Surgery, radiation therapy, or a drug treatment to stop the functioning of the ovaries. Also called ovarian ablation.
ovary(OH-vuh-ree) One of a pair of female reproductive glands in which the ova, or eggs, are formed.
over-the-counterThe over-the-counter (OTC) or unlisted market maintained by securities dealers for issues not listed on a stock exchange.
Over-the-Counter DrugYou don't need a prescription to obtain over-the-counter drugs.
Over-the-Counter Drugs (OTC)(OTC)FDA defines OTC drugs as safe and effective for use by the general public without a doctor's prescription.
overactive thyroid(... THY-royd) Too much thyroid hormone. Symptoms include weight loss, chest pain, cramps, diarrhea, and nervousness. Also called hyperthyroidism.
overall survival rate(... ser-VY-vul ...) The percentage of people in a study or treatment group who are alive for a certain period of time after they were diagnosed with or…
overdose(OH-ver-DOHS) An amount of drug that is more than what should be taken at one time.
overexpress(OH-ver-ek-SPRES) In biology, to make too many copies of a protein or other substance.
overgrowth syndrome(OH-ver-grohth SIN-drome) A group of genetic disorders in which there is an abnormal increase in the size of the body or a body part that is often noted…
overweightBeing too heavy for one's height. Excess body weight can come from fat, muscle, bone, and/or water retention.
ovulation(ov-yoo-LA-shun) The release of an egg from an ovary during the menstrual cycle.
OX-40A protein being studied in the treatment of cancer. Substances that attach to OX-40 on the surface of T cells (a type of white blood cell) may help the T…
oxaliplatin(ok-SAL-ih-pla-tin) A drug used to treat colorectal cancer that is advanced or has come back.
oxandrolone(ox-AN-dro-lone) A drug used to help patients gain weight after injury, chronic infection, or severe illness.
OXi-104A substance that blocks the process cells use to repair DNA. It may help anticancer drugs and radiation kill more cancer cells.
oxidationProcess in which molecules are split to give products that have unpaired electrons.
oxidative metabolismA chemical process in which oxygen is used to make energy from carbohydrates (sugars).
oxidative stressA condition in which antioxidant levels are lower than normal. Antioxidant levels are usually measured in blood plasma.
oxide(OK-side) A type of chemical substance that is a combination of oxygen and another substance. Oxides are found in essential oils.
oxycodone(OK-see-KOH-done) A morphine-like drug used to treat medium to severe pain. It belongs to the family of drugs called opioid analgesics and may be…
oxygen(OK-sih-jen) A colorless, odorless gas. It is needed for animal and plant life.
oxygen saturation test(OK-sih-jen SA-chuh-RAY-shunâ¦) A test that measures the amount of oxygen being carried by red blood cells.
oxygen therapy(OK-sih-jen THAYR-uh-pee) Treatment in which a storage tank of oxygen or a machine called a compressor is used to give oxygen to people with breathing…
P-32A radioactive form of the element phosphorus used in the treatment of cancer.
p-valueA statistics term. A measure of probability that a difference between groups during an experiment happened by chance.
p53 geneA tumor suppressor gene that normally inhibits the growth of tumors. This gene is altered in many types of cancer.
pacemaker(PAYS-may-ker) An electronic device that is implanted in the body to monitor heart rate and rhythm.
Pacific valerianA plant whose roots are used as a sedative and to treat certain medical conditions.
pack yearA way to measure the amount a person has smoked over a long period of time. It is calculated by multiplying the number of packs of cigarettes smoked per…
paclitaxel(PA-klih-TAK-sil) A drug used to treat breast cancer, ovarian cancer, and AIDS-related Kaposi sarcoma.