Use the A-Z list to browse more than 6,000 health-related topics in our library. Clicking on a term opens the definition and, in most cases, links to more information.
"OT" is more commonly referred to as "Occupational Therapist" in the medical community. Occupational Therapist
A healthcare professional trained to evaluate and treat people whose abilities are impaired by physical illness injury or developmental deficiencies. Certification standards vary by state and some states require a license to practice. More Information on Occupational Therapist: Pain Basics
"Otaliga" is more commonly referred to as "Ear Pain" in the medical community. Ear Pain
Also Known As: "Primary Otalgia, Earache, Referred Otalgia, Ear Pressure, Ear Discomfort"
Pain that is felt in the ear. Many ear conditions may cause pain, including infections, pressure changes, disorders in shared structures (e.g., nose, sinuses, jaw) and shingles that spreads to the facial nerve (Ramsay Hunt Syndrome). More Information on Ear Pain: Ear, Eye & Face Pain
Along with cigarettes and other smoked tobacco products, ''smokeless'' chewing tobacco and ''snuff'' are harmful to the body. People who smoke non-tobacco products (e.g., marijuana) also face serious health risks. More Information on Other Smoking Products: Smoking & Tobacco
"Otitis Externa" is more commonly referred to as "Swimmer's Ear" in the medical community. Swimmer's Ear
Also Known As: "External Ear Infection, External Otitis"
Inflammation and irritation of the outer ear canal. It is generally due to a bacterial or fungal infection caused by water trapped in the ear canal. Symptoms include itching, pain, redness and discharge. More Information on Swimmer's Ear: Ear Conditions
Infection or inflammation of the middle ear caused by bacteria or viruses. Most cases in children develop after a cold or the flu. People with chronic allergies are at higher risk for this condition. More Information on Otitis Media: Ear Conditions
Also Known As: "Secretory Otitis Media, Nonsuppurative Otitis Media"
Inflammation of the middle ear (otitis media) without infection, accompanied by a buildup of fluid (effusion). More Information on Otitis Media with Effusion: Ear Conditions
Also Known As: "ENT MD, ENT Physician, Ear, Nose & Throat Physician"
Physicians trained in the diagnosis, management and treatment of conditions of the ears, nose and throat and related structures of the head and neck. More Information on Otolaryngologist: Nose & Throat
A handheld device with a light and magnifying glass that is used by medical professionals to see a patient's ear drum. More Information on Otoscope: Ear Conditions
Any number of triggers present in an outdoor environment that can contribute to allergic reaction in sensitive people. The term is primarily used to describe airborne allergens such as pollen, but a number of other outdoor allergens exist. More Information on Outdoor Allergens: Outdoor Allergies
It is important to remain safe when outdoors and during seasonal traditions. Children are particularly vulnerable to extremes of temperature and injury during these excursions. More Information on Outdoor Safety & Children: Pediatric First Aid & Safety
"Outpatient Cardiac Catheterization" is more commonly referred to as "Cardiac Catheterization" in the medical community. Cardiac Catheterization
Also Known As: "Heart Catheterization, Ambulatory Cardiac Catheterization, Catheterization, Cardiac Cath, Arterial Catheterization"
The process by which a catheter is inserted by a physician into a blood vessel and all the way to the heart, in order to obtain information about the heart and the coronary arteries. This term may also describe catheter-based procedures. More Information on Cardiac Catheterization: Catheter Tests & Procedures
"Ovarian Amenorrhea" is more commonly referred to as "Amenorrhea" in the medical community. Amenorrhea
Also Known As: "Absent Menstruation, Dietary Amenorrhea, Absent Periods, Primary Amenorrhea, Emotional Amenorrhea, Absent Menses, Secondary Amenorrhea"
Absence of menstruation. This may be normal, such as before puberty, during pregnancy and lactation and after menopause. Or, it may be caused by congenital abnormalities, anorexia, endocrine disorders, hormonal imbalances or metabolic conditions. More Information on Amenorrhea: ObGyn Signs & Symptoms
Cancer that begins in the cells that compose the ovaries, including surface epithelial cells, germ cells, and the sex cord-stromal cells. Ovarian cancer ranks as the fourth leading cause of cancer death in women. More Information on Ovarian Cancers: ObGyn Cancer
A fluid-filled structure within or on an ovary. Functional cysts, a normal part of ovulation, form each month in most healthy women who do not use birth control pills. Abnormal cysts can be benign (including dermoid cysts) or cancerous. More Information on Ovarian Cysts: Uterine & Ovarian Health
A disease in which malignant (cancer) cells form in the germ (egg) cells of the ovary. Ovarian germ cell tumors usually occur in teenage girls or young women and most often affect just one ovary. More Information on Ovarian Germ Cell Tumor: ObGyn Cancer
A rare condition where the ovaries develop too many follicles due to ovarian stimulation with fertility medications. More Information on Ovarian Hyperstimulation Syndrome: Fertility Issues
"Ovarian Insufficiency" is more commonly referred to as "Premature Ovarian Failure" in the medical community. Premature Ovarian Failure
Also Known As: "Premature Menopause, POF"
A condition in woman under age 40 in which the ovaries stop making eggs and certain hormones. It usually but not always causes infertility. More Information on Premature Ovarian Failure: Uterine & Ovarian Health
"Ovarian Pregnancy" is more commonly referred to as "Ectopic Pregnancy" in the medical community. Ectopic Pregnancy
Also Known As: "Tubal Pregnancy, Abdominal Pregnancy, Cervical Pregnancy, Interstitial Pregnancy"
Pregnancy in which a fertilized egg develops outside the uterus, usually in the fallopian tubes (interstitial) but sometimes in the cervix, ovary or abdomen. The embryo must be removed to prevent rupture of internal organs. More Information on Ectopic Pregnancy: Pregnancy Basics
Use of oral or injected medication to stimulate the ovaries to develop follicles and eggs. More Information on Ovarian Stimulation: Uterine & Ovarian Health
"Ovariectomy" is more commonly referred to as "Oophorectomy" in the medical community. Oophorectomy
Also Known As: "Bilateral Salpingo Oophorectomy, Unilateral Oophorectomy, Salpingo Oophorectomy, Bilateral Oophorectomy, Salpingectomy Oophorectomy, Bilateral Ovariectomy, Ovary Removal"
Surgical removal of one (unilateral) or both (bilateral) ovaries. It is used to treat cancers, cysts or uterine disorders. It may be performed alone of in combination with removal of the uterus (hysterectomy) or fallopian tubes (salpingectomy). More Information on Oophorectomy: Uterine & Ovarian Health
A pair of reproductive organs in the female pelvis on either side of the uterus that produce hormones (e.g., estrogen) and eggs (ova). Released monthly into the uterus, eggs may be fertilized by sperm (pregnancy), or shed during menstruation. More Information on Ovaries: ObGyn Cancer
Cancer that begins in the cells that compose the ovaries, including surface epithelial cells, germ cells, and the sex cord-stromal cells. Ovarian cancer ranks as the fourth leading cause of cancer death in women. More Information on Ovary Cancers: ObGyn Cancer
"Ovary Removal" is more commonly referred to as "Oophorectomy" in the medical community. Oophorectomy
Also Known As: "Bilateral Salpingo Oophorectomy, Unilateral Oophorectomy, Salpingo Oophorectomy, Ovariectomy, Bilateral Oophorectomy, Salpingectomy Oophorectomy, Bilateral Ovariectomy"
Surgical removal of one (unilateral) or both (bilateral) ovaries. It is used to treat cancers, cysts or uterine disorders. It may be performed alone of in combination with removal of the uterus (hysterectomy) or fallopian tubes (salpingectomy). More Information on Oophorectomy: Uterine & Ovarian Health
A condition in which the bladder contracts involuntary during the time the bladder is filling. Its most common symptom is urinary incontinence. More Information on Overactive Bladder: Urinary & Bladder
"Overactive Thyroid" is more commonly referred to as "Hyperthyroidism Basics" in the medical community. Hyperthyroidism Basics
Also Known As: "Thyrotoxicosis"
A condition in which the thyroid gland produces too much of the hormone thyroxine. As a result, the body's metabolism speeds up, which can cause weight loss, rapid heartbeat and other symptoms. More Information on Hyperthyroidism Basics: Thyroid & Parathyroid
A removable prosthetic device supported by implants or the roots of at least two natural teeth to provide better stability for the denture. More Information on Overdenture: Bridges, Dentures & Implants
A group of rare syndromes present at birth in which body size or internal organs are enlarged or overgrown. Many of these syndromes increase the risk of cancer. More Information on Overgrowth Syndromes: Cancer Risk Factors
"Overnight Hypoglycemia" is more commonly referred to as "Nocturnal Hypoglycemia" in the medical community. Nocturnal Hypoglycemia
Also Known As: "Nighttime Hypoglycemia"
Low blood sugar (glucose) levels that occurs in the overnight hours when a patient is asleep. It may lead to symptoms such as insomnia, night sweats, restlessness or nightmares. More Information on Nocturnal Hypoglycemia: Glucose
A form of malnutrition that develops when nutrients are consumed in amounts that exceed those needed for good health. In the United States, this most often occurs as a result of excess calories, fats, saturated fats and cholesterol. More Information on Overnutrition: Nutrition Basics
A term used to describe diabetes mellitus when the condition is producing obvious symptoms, such as the need to urinate frequently or excessive thirst. More Information on Overt Diabetes: Diabetes & Endocrine Basics
"Overuse Syndrome" is more commonly referred to as "Repetitive Motion Disorders" in the medical community. Repetitive Motion Disorders
Also Known As: "Cumulative Trauma Disorders"
A musculoskeletal condition resulting from repeated motions performed during work, leisure or other activities. Examples include tendinitis, bursitis, carpal tunnel syndrome and tennis elbow. More Information on Repetitive Motion Disorders: Pain Basics
An excess of body mass, as reflected in individuals with a body mass index (BMI) greater than 25 and less than 30. BMI is defined as weight in kilograms divided by height in meters squared (Wt/Ht2). More Information on Overweight: Weight & Obesity Basics
The type of protein found in egg yolks. People with egg allergies may need to avoid foods containing ovoalbumin. More Information on Ovoalbumin: Food Allergy & Intolerance
The type of protein found in egg whites. People with egg allergies may need to avoid foods containing ovoglobulin. More Information on Ovoglobulin: Food Allergy & Intolerance
A lubricating substance (mucin) found in eggs. People with egg allergies may need to avoid foods containing ovomucin. More Information on Ovomucin: Food Allergy & Intolerance
A substance (vitelia) found in eggs that may trigger an allergic reaction in sensitive individuals. People with egg allergies may need to avoid foods with ovovitelia listed in the ingredients. More Information on Ovovitelia: Food Allergy & Intolerance
The process by which an ovary releases a mature egg into the fallopian tube, often around day 14 of a 28-day menstrual cycle. More Information on Ovulation: Uterine & Ovarian Health
Medications that induce ovulation. They are commonly used in fertility treatments and may cause a higher than normal incidence of multiple fetuses, increasing the risk to both the mother and fetuses. More Information on Ovulation Drugs: Fertility Issues
Medications that induce ovulation. They are commonly used in fertility treatments and may cause a higher than normal incidence of multiple fetuses, increasing the risk to both the mother and fetuses. More Information on Ovulation Medications: Fertility Issues
Pain that occurs when the ovary releases and egg (ovulation), which is usually about mid-cycle. Occurs regularly in some women. Since only one ovary produces an egg each month, the pain occurs on one side of the body at a time. More Information on Ovulation Pain: ObGyn Signs & Symptoms
Over-the-counter tests that indicate the day of ovulation. Some tests measure the amount of luteinizing hormone (LH) in the urine, others measure estrogen levels. More Information on Ovulation Predictor Tests: Fertility Issues
Over-the-counter tests that indicate the day of ovulation. Some tests measure the amount of luteinizing hormone (LH) in the urine, others measure estrogen levels. More Information on Ovulation Tests: Fertility Issues
"Oxacillin" is more commonly referred to as "Penicillins" in the medical community. Penicillins
Also Known As: "Ticarcillin, Dicloxacillin, Nafcillin, Amoxicillin, Cloxacillin, Carbenicillin, Ampicillin"
A class of antibiotics, medications that kill or slow the growth of harmful microorganisms, such as bacteria. They have no effect on viruses. Examples include penicillin, amoxicillin, ampicillin and dicloxacillin, among others. More Information on Penicillins: Cold & Infections Medications
An organic acid in leafy green vegetables, chocolate, tea, nuts, tomatoes and other foods that binds to calcium to form calcium oxalate. The body cannot absorb this insoluble compound, which may lead to kidney-stone formation.
An organic acid in leafy green vegetables, chocolate, tea, nuts, tomatoes and other foods that binds to calcium to form calcium oxalate. The body cannot absorb this insoluble compound, which may lead to kidney-stone formation.
A four-carbon intermediate compound in the citric acid cycle. Acetyl CoA combines with free oxaloacetate in the mitochondria, forming citric acid and beginning the citric acid cycle.
Addition of oxygen, removal of hydrogen or removal of electrons from an element or compound. Oxygen attaches to the double bonds of unsaturated fatty acids. This causes fats to become rancid.
A term sometimes used to describe the premature fusing of all sutures of the skull, but may be used to characterize the fusing of the coronal suture, which unite the front and side bones of the skull, plus other premature fusings in the skull. More Information on Oxycephaly: Pediatric Brain & Nerve
"Oxycodone" is more commonly referred to as "Codeine" in the medical community. Codeine
Also Known As: "Tramadol, Dezocine, Hydrocodone, Propoxyphene, Dalgan, Dihydrocodeine"
A type of narcotic analgesic, medications that reduce pain and most also reduce inflammation. They do not eliminate pain, but mask it by increasing the body's pain threshold. More Information on Codeine: Pain Medications
A colorless, tasteless gas that makes up about 21 percent of the air. High concentrations of oxygen are sometimes given to patients through a mask or tent as a treatment for breathing-related conditions (oxygen-replacement therapy).
A complex energy system that requires oxygen. To release ATP, this system completes the breakdown of carbohydrate and fatty acids via the citric acid cycle and electron transport chain.
"Oxygen Free Radicals" is more commonly referred to as "Free Radicals" in the medical community. Free Radicals
Short-lived, reactive chemicals often derived from oxygen-containing compounds that damage cells, especially DNA and cell membranes. They are common byproducts of normal chemical reactions occurring in cells.
"Oxygen Saturation Test" is more commonly referred to as "Pulse Oximetry" in the medical community. Pulse Oximetry
A painless test in which a small sensor is placed on the patient's finger or earlobe to measure the amount of oxygen in the patient's blood. It works by measuring the amount of specific types of light that are absorbed by body tissue.
"Oxygenated Water" is more commonly referred to as "Structured Water" in the medical community. Structured Water
Also Known As: "Clustered Water, Activated Water, Hexagonal Water, Pentagonal Water, Alkanized Water, Hydrogenated Water, Super Ionized Water"
Waters which supposedly have nutritional or spiritual value based on the physical structure of the water's atoms. These claims are widely rejected by the scientific community. More Information on Structured Water: Water & Hydration
"Oxygenator Bypass Machine" is more commonly referred to as "Heart Lung Machine" in the medical community. Heart Lung Machine
Also Known As: "Lung Heart Machine, Extracorporeal Circulation Machine, Heart Lung Bypass Machine, Pump Oxygenator"
A machine that takes over the heart's functions when the heart is stopped during open-heart surgery. A heart-lung machine enables cardiopulmonary bypass, or the procedure of circulating blood and oxygen for a patient during open-heart surgery. More Information on Heart Lung Machine: Bypass Surgery
"Oxymorphone" is more commonly referred to as "Anileridine" in the medical community. Anileridine
Also Known As: "Levorphanol, Nalbuphine, Buprenorphine, Hydromorphone, Butorphanol, Pentazocine"
A type of narcotic analgesic, medications that reduce pain and most also reduce inflammation. They do not eliminate pain, but mask it by increasing the body's pain threshold. More Information on Anileridine: Pain Medications
"Oxytetracycline" is more commonly referred to as "Tetracyclines" in the medical community. Tetracyclines
Also Known As: "Doxycycline, Methacycline, Minocycline, Demeclocycline"
Any of a class of antibiotics, medications that kill or slow the growth of harmful microorganisms, such as bacteria. They have no effect on viruses. More Information on Tetracyclines: Cold & Infections Medications
A hormone produced in the pituitary gland of the brain which stimulates contraction of the uterus during childbirth, and stimulates milk production. More Information on Oxytocin: Pregnancy Basics
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