Words to Know

opiate

A substance used to treat pain or cause sleep. Opiates are made from opium or have opium in them. Opiates bind to opioid receptors in the central nervous system. Examples of opiates are codeine and morphine. An opiate is a type of analgesic agent.

opioid

A substance used to treat moderate to severe pain. Opioids are similar to opiates, such as morphine and codeine, but are not made from opium. Opioids bind to opioid receptors in the central nervous system. Opioids used to be called narcotics. An opioid is a type of alkaloid.

opportunistic infection

An infection caused by an organism that does not normally cause disease. Opportunistic infections occur in people with weakened immune systems.

oral

By or having to do with the mouth.

organ

A part of the body that performs a specific function. For example, the heart is an organ.

orthodox medicine

A system in which medical doctors and other healthcare professionals (such as nurses, pharmacists, and therapists) treat symptoms and diseases using medicines, radiation or surgery. Also called allopathic medicine, biomedicine, conventional medicine, mainstream medicine and Western medicine.

osteolytic

Causing the breakdown of bone.

osteonecrosis of the jaw

Also called "dead jaw," jaw necrosis. Painful exposed bone in the jaw. Women who undergo radiation or chemotherapy or who receive steroids as part of breast cancer treatment are at increased risk for this condition. Women who take bisphosphonates may also be at risk for jaw necrosis.

osteopenia

A condition in which there is a lower-than-normal bone mass or bone mineral density (the amount of bone mineral contained in a certain amount of bone). Osteopenia is a less severe form of bone loss than osteoporosis.

osteoporosis

A condition that is marked by a decrease in bone mass and density, causing bones to become fragile.

OTC

Over-the-counter. Also called nonprescription. A medicine that can be bought without a prescription (doctor's order). Examples include analgesics (pain relievers) such as aspirin and acetaminophen (brand name, Tylenol).

outcome

A specific result or effect that can be measured. Examples of outcomes include decreased pain, reduced tumor size, and improvement of disease.

outpatient

An individual who visits a health care facility for diagnosis or treatment without spending the night. Sometimes called a day patient.

ovarian

Having to do with the ovaries, the female reproductive glands in which the ova (eggs) are formed. The ovaries are located in the pelvis, one on each side of the uterus.

ovarian ablation

Also called ovarian suppression. Surgery, radiation therapy, or treatment with medicines to stop the functioning of the ovaries.

ovarian cancer

Cancer that forms in tissues of the ovary (one of a pair of female reproductive glands in which the ova, or eggs, are formed). Most ovarian cancers are either ovarian epithelial carcinomas (cancer that begins in the cells on the surface of the ovary) or malignant germ cell tumors (cancer that begins in egg cells).

ovarian suppression

Also called ovarian ablation. Surgery, radiation therapy, or a treatment with medicine to stop the functioning of the ovaries.

ovary

One of a pair of female reproductive glands in which the ova, or eggs, are formed. The ovaries are located in the pelvis, one on each side of the uterus.

over-the-counter

Also called OTC, or nonprescription. A medicine that can be bought without a prescription (doctor's order). Examples include analgesics (pain relievers) such as aspirin and acetaminophen (brand name, Tylenol).

overall survival rate

Also called survival rate. The percent of people in a study or treatment group who are alive for a certain period of time after they were diagnosed with or treated for a disease, such as breast cancer. The overall survival rate is often stated as a 5-year survival rate, which is the percent of people in a study or treatment group who are alive 5 years after diagnosis or treatment.