Medical Terms Glossary

Customer Feedback

You are here: Home > Essential Ideas Reference Area > Medical Terms Glossary
We found 0 results matching your criteria.

This glossary is not meant to be used to diagnose any disease or condition of the body. It is presented for use as an educational reference only. Consult with a qualified health professional for proper diagnosis of any disease, illness, or condition of the body.



Further Sources


Acne is a blockage of a skin pore by dead skin cells, tiny hairs, and oil secreted by the sebaceous glands located near hair follicles in the face, neck, and back. This blockage occurs deep within the skin. Acne is not caused by dirt on the face or by eating certain foods. Over scrubbing the face may actually make acne worse.

For more information, visit the website of the American Academy of Dermatologists at, or the National Institute of Arthritis and Musculoskeletal and Skin Diseases at .


Alcoholism is an increasing dependency on alcohol that interferes with health, career, or family and social interactions. This problem affects between 5-10% of all people who use alcohol. Alcoholism has also been defined as any irresponsible drinking (such as binge drinking, or drunk driving).


An allergy is an immune response to a harmless substance that most people don’t react to. Allergies can cause sneezing, stuffy or runny noses, hives, itching, red eyes, breathing problems, stomach cramps, or vomiting.

Alopecia Areata

Alopecia Areata is an autoimmune disease where the body’s immune system attacks fast-growing cells in the hair follicles, causing patches of hair, or all of the hair to fall out.

For more information, visit the National Institute of Arthritis and Musculoskeletal and Skin Diseases:


A substance that acts as a pain reliever


Anemia is a lack of red blood cells in the body resulting in weakness and impaired motor and mental development. It is most common in infants and small children and is often (although not always) caused by a deficiency of iron in the diet.

For more information, visit


A swelling or dilation of a blood vessel in the area of a weakened blood vessel wall.


A psychological disorder where an individual is addicted to depriving themselves of food.


Chronic inflammation of the mucus membranes in the nose and throat.


A thickening or hardening of the artery walls due to high blood pressure, calcification, or fatty deposits.


Arthritis is any painful swelling of a joint.


Asthma is a disease that causes the lung’s airways to narrow, making it difficult to breath. Episodes (or attacks) of asthma can be triggered by any number of things, including smoke, pollution, dust mites, and other allergens.

For more information, visit


Attention Deficit/Hyperactive Disorder is a psychological condition characterized by inattentiveness, restlessness, and difficulty concentrating.

For more information, visit


Autism is a disorder caused by an abnormality in the brain which makes it difficult for an individual to communicate or interact with other people.

For more information, visit


Baldness is usually caused by the hair follicles in the scalp failing to replace the hair when it falls out. This failure to replace the hairs is typically attributed to either aging, hormone imbalance, or an increase in the male hormone testosterone.


Boils (Furuncles) are infections of the upper layers of the skin by staphylococcus or streptococcus bacteria. These infections often become filled with pus and dead cells, causing painful pea to golf ball sized swellings


Inflammation of the bronchi (the tubes that lead from the trachea to the lungs).


A bruise is an injury to tissue that results in blood capillaries breaking and spilling blood into the tissue.


Bulimia is a chronic psychological desire to purge the body of recently eaten foods either through vomiting or through the abuse of laxatives.


A callus is a thickening of the outer layer of skin in a small area caused by friction or rubbing. Calluses can sometimes lead to serious infections.


Cancer is when damaged or abnormal DNA causes a cell to divide out of control, resulting in clumps of rapidly dividing cells, or tumors, within healthy tissue.


A cataract is a clouding of the lens of an eye, causing blurriness, double-vision, or blindness. Cataracts can be caused by medications, injury, disease, or the natural aging process.


Fat deposits.

Charlie Horse

A Charlie horse, or painful muscle spasm in the calf, is often caused by overuse, dehydration, or a lack of potassium, sodium, calcium, or magnesium in the body. Stretching the muscle and applying an initial hot compress, followed by a cold compress or ice pack once the pain starts to subside can often alleviate the pain associated with a muscle spasm.


Chiggers are the parasitic larvae of certain types of mites found in wooded areas, or areas of high grass. When chiggers bite, they cause red, severely itching bumps to appear.


Cholera is a bacterial illness that can cause severe diarrhea, vomiting, and leg cramps. The most important treatment for cholera is to re-hydrate the body by drinking large amounts of an oral rehydration solution. (In an emergency when no commercially prepared rehydration solution is available, mix 6 tsp. sugar, ½ tsp. salt, and 1 liter of water and drink.)


Involuntary twisting, jumping, dancing, or other coordinated body movements that interfere with normal movement. Often caused by a previous strep (streptococcus) infection. A sign of rheumatic fever.


Periods of loud crying in young infants that seem to be caused by pain in the abdomen.


Inflammation of the large intestine.


Also called “pinkeye” or “red eye”, conjunctivitis is an inflammation of the membrane that covers the whites of the eyes and the inside of the eyelid due to infection, allergies, or irritation.


Uncontrolled rapid contracting and relaxing of muscles, usually caused by a seizure (sudden random electrical activity in the brain).


A small, sometimes painful, callus caused by the friction between a bone and an outside pressure (such as a shoe) on the intermediate tissues.


A natural hormone created in the outer layers of the adrenal gland that has anti-inflammatory and anti-arthritic properties. Cortisone has also been synthetically developed as a drug for rheumatoid arthritis.

Crohn’s Disease

A disease that causes chronic ulceration (either mild or severe) of the large and sometimes the small intestine.

Cushing’s Disease

(or Cushing Syndrome) describes many different symptoms (including weight gain, weakness, bruising, & osteoporosis)caused by an overabundance of the cortisol hormone. This disease is often caused by taking artificial cortisone or cortisone-like substances

Cystic Fibrosis

Cystic fibrosis is a potentially deadly genetic disease that causes an excess of mucus to build up, inhibiting pancreas function and slowly clogging the airways.


Dermatitis is redness, itching or soreness of the skin caused either by an allergic reaction or contact with a skin irritant.

Diaper Rash

Irritation of the skin in the area covered by the diaper caused by infection, sweat, friction, or allergic reactions.


Diphtheria is a rare bacterial infection that causes sore throat, low fevers, and swelling of the neck and throat that can possibly lead to airway obstruction and other complications.


Any substance that causes an increase in the amount of urine created by the body.

Down Syndrome

Down Syndrome is a genetic condition characterized by an extra chromosome 21. This extra chromosome causes the formation of various distinguishing physical attributes, and slight to severe mental disabilities or retardation.


Dysentery is a painful intestinal inflammation due to an infection of the intestine by an ameba, causing severe cramping, diarrhea, vomiting, and bloody stools. Rehydration is critical to anyone suffering from dysentery.


Itchy or painful patches of inflamed skin caused by allergic reactions, irritating substances, infection, or disease.


A swelling in the body caused by the accumulation of water, blood, or other fluids.


Any substance that acquires the ability to conduct electricity when it is dissolved in a solution. Sodium, calcium, and potassium are three electrolytic substances that play an important role in the body. Low levels of any of these substances in the blood can lead to muscle cramps and other problems.


Damaged or burst air sacs in the lungs caused by smoking or a long-lasting lung infection.


An enzyme is any biological agent that mediates the speed or frequency of chemical reactions.


Being unable to work or think at full capacity.


Complex carbohydrates that cannot be digested by the body. Fiber serves to help clean the colon and regulate bowel movements. Fiber can be found in fruits, vegetables, whole grain breads and cereals.


A benign tumor found in the uterus that can cause pain, reproductive problems, or heavy menstrual bleeding.


A fever is defined as any body temperature above 98.6 degrees F. A fever is the body’s natural way of fighting disease (many pathogens cannot survive, or are weakened in these elevated temperatures). High (over 104 degrees F.) fevers, however, can cause convulsions and other undesired effects.


(Fibromyalgia) A condition of generalized chronic pain and tender spots where tiny movements can bring on pain. Since there are very few positive findings, it is difficult to diagnose. Studies have shown that regular aerobic exercise may reduce the level of pain.


(Influenza) Any of several viral diseases that cause fever, nausea, fatigue, soreness, impaired breathing, and other cold-like symptoms.


Localized decay of body tissue caused by a loss of blood to that area.

Gas gangrene is caused by bacteria invading a deep wound that has lessened the blood supply, or cut it off entirely. The bacteria create gases and pus in the infected area, causing severe pain and accelerating decay of the tissue.


A gum disease that results in sore gums that bleed easily. This condition can sometimes be corrected with more frequent/longer brushing and flossing.


Glaucoma is an increasing eye pressure caused by a slowing in fluid drainage from the eye. Glaucoma can cause damage to the optical nerve or loss of sight over time.


An enlarged thyroid gland. Goiter is often attributed to a deficiency of iodine in the body (found in iodized salts). While this is one possible cause, goiter is often a symptom of any of several diseases or conditions.


Gout is a painful inflammation of a joint caused by a buildup of uric acid crystals deposited in the joint. Uric acid is formed during the natural breakdown of dead tissues in the body. An excess of uric acid in the bloodstream can lead to the formation of crystals in the joints or kidneys (kidney stones). Some good ways to prevent the formation of uric acid crystals include maintaining a healthy body weight (which leaves less body tissue to be broken down), exercise, and drinking plenty of water.

Grave’s Disease

Toxicity of the thyroid gland which leads to goiter, an autoimmune skin disease, and an eye disease that often causes bulging of the eyes.

Hashimoto’s Disease

An autoimmune disease of the thyroid gland, leading to goiter and a decreased ability of the thyroid to produce essential hormones.


A burning pain in the chest caused by stomach acid rising up into the esophagus.


Any internal or external bleeding.


Hepatitis is a liver disease caused by one of five different Hepatitis viruses. The symptoms and seriousness of the disease depend on the type of virus causing the disease.

For more information, visit


A hernia is the protrusion of any tissue or organ outside of the cavity in which it is normally contained.

High Blood Pressure

Blood pressure that is consistently higher than 140 over 90. Chronic high blood pressure can cause severe health problems. High blood pressure can often be reduced by losing weight if overweight, cutting back on salty foods, and regular exercise.

Hodgkin’s Disease

Hodgkin disease is a cancer that develops in the lymph system, causing enlarged lymph nodes, fever, sweating, fatigue, and loss of weight.


Inflammation is the body’s response to infection, irritation, or injury in a localized area. The tissue becomes inflamed due to dilation of the blood vessels (which allows greater blood flow into the affected area).


Lack of adequate sleep. Insomnia is caused by a variety of factors, including stress, disease, the environment, overuse of caffeine and other stimulants, and changes in sleeping times or behaviors.

Irritable Bowel Syndrome

Chronically irregular bowel movements that result in frequent bouts of constipation and diarrhea.

Jet Lag

Jet lag is caused by the hypothalamus (the body’s internal clock) trying to re-adjust the body’s schedule to differing environmental cues (such as when the sun rises) after a person has traveled rapidly across different time zones.


Inflammation of the larynx due to viral or bacterial infection. Often causes hoarseness, or voice loss.


Lice are any of three varieties of small, parasitic insects that are found either on the head, body, or pubic hair. Lice can be passed to another person through personal contact or by sharing bed linens, clothing, hats, hair ribbons, scarves, combs or brushes.

Lou Gehrig’s Disease

Lou Gehrig’s disease (or ALS) is caused by the atrophy of certain nerve cells in the body that control voluntary movement. This atrophy leads to weakness in the muscles controlled by these nerve cells. Lou Gehrig’s disease usually leads to death within several years due to opportunistic infections overcoming an already weakened body.

Lyme Disease

Lyme disease is a disease caused by an infection of B. Burgdorferi bacteria transmitted by the bite of a deer tick. Symptoms of Lyme disease include a red circular rash, arthritis, neurological problems, and possible heart irregularities.

For more information on Lyme disease, visit:


Malaria is a disease caused by one of four types of parasites transmitted to humans from several species of mosquitoes. Symptoms can include muscle pains, headaches, fevers, sweating, and chills. More serious cases involve anemia and kidney failure that can lead to death.

For more information, visit


A type of malignant skin cancer that presents itself as a rapidly growing/spreading, irregularly shaped mole. This type of cancer can be very dangerous if not detected and treated early.


The natural cessation of menstruation in women associated with a decline in the ovary hormones estrogen and progesterone.


The entire range of chemical processes that build up and break down substances within the body.

Migraine Headaches

A throbbing headache caused by spasms in the brain’s blood vessels. Sometimes accompanied by an “aura”— perception of lights, or sounds that do not exist.


Mold is a type of fungus that grows in damp, warm conditions. The CDC recommends using a weak bleach solution (1 part bleach, 10 parts water) to remove any mold growths within the house.

For more information, visit


Mononucleosis—an illness characterized by fever, sore throat, fatigue, and swollen lymph nodes—is caused by an infection of the Epstein-Barr virus during adolescence or early adulthood. The Epstein-Barr virus is very common in humans (it can be found in 95% of people over the age of 40), and many people acquire the virus with few or no symptoms during infancy and early childhood. When an individual acquires the virus during adolescence and early adulthood, it can sometimes develop into mononucleosis (about 35-50% of the time).

For more information, visit


Mumps is a viral disease that causes fever, sore muscles, headache, and swelling of the lymph nodes by the jaw.

For more information, visit

Muscular Dystrophy

Any of several genetic diseases that cause gradual weakening of the skeletal muscles.

Myelin Sheath

The myelin sheath is the fatty protective layer that surrounds the nerve fibers allowing nerve cells to transmit their signals properly. It is composed of lipids (70%), and proteins (30%). It is produced by oligodendrocyte cells surrounding the nerve fibers.


Inflammation of the nerve cells.


Any nerve malfunction or disease.


Inflammation of the pancreas, often associated with alcohol or gallstones.

Parkinson’s Disease

A neurological disease that over time causes progressively worse shaking, muscle weakness, and other symptoms.


(Sore throat) Inflammation of the Pharynx (throat).


Inflammation or swelling of a vein, usually caused by a blood clot.


Plague is a potentially deadly bacterial disease that is caused by the Yersinia pestus bacteria transmitted to humans and animals through close contact or bites from fleas that have previously bitten infected animals. Symptoms include fever, headaches, and extremely swollen and hot lymph nodes. If left untreated, plague can quickly invade the lungs causing severe pneumonia, high fever, bloody coughing, and death.

For more information, visit


Pleurisy is the inflammation of one or both of the two protective layers that surround the lungs. This inflammation causes sharp pains that are intensified by breathing. Pleurisy can be caused by infection, injury, blood clots, or disease.

Poison Oak/Ivy

These two plants create a chemical that is caustic to the skin, causing inflammation, redness, itching, and pain in the areas it comes in contact with.


An outgrowth of tissue on the inside of hollow organs.


A female hormone produced by the ovaries responsible for regulating the lining of the uterus.


Psoriasis is a chronic skin disease that causes skin cells to be rotated to the surface before they are mature, resulting in inflamed patches of scaly, red skin that either itch or are sore. About 20% of the time, psoriasis also causes arthritis in adjoining joints. Psoriasis occurs when T cells (white blood cells that help fight infections) become unnecessarily active, triggering inflammation and causing skin cells to rotate to the surface before they are mature. One possible treatment for the itching and soreness is to soak for 15 minutes in a bath with Epsom or dead sea salts, oiled oatmeal, or oil, followed by application of a moisturizer on the affected areas.

For more information, visit


Radiation is any of several different forms of energy that may or may not be harmful to the human body. Common forms of radiation include light, radio waves, and x-rays. The three types of radiation considered most dangerous to humans include alpha particles (large, slow moving particles that typically bounce off the skin, and are not dangerous unless the source of these particles is ingested into the body), beta particles (tiny, fast moving particles that can penetrate deep within the body when emitted within several thousand feet), and gamma rays (bursts of energy that can penetrate deep within the body). Each of these types of radiation can change the chemical state or break chemical bonds of molecules they collide with, potentially damaging vital life processes within a cell.

For more information, visit

Rheumatic Fever

An illness that causes pain in the joints, fever, nausea, and vomiting. This disease follows an infection by the streptococcus bacteria or scarlet fever. Rheumatic fever can cause severe damage to the heart, joints, and brain. Rheumatic fever often returns once a person develops it.


Ringworm is a skin disease cause by a fungus that can result in ring-shaped red rashes that can be itchy, crusty or scaly.

Saint Vitus Dance

(Sydenham Chorea) Involuntary twisting, jumping, dancing, or other coordinated body movements that interfere with normal movement. Often caused by a previous strep (streptococcus) infection. A sign of rheumatic fever.


Scabies is an infestation of a microscopic mite (Sarcoptes scabei) that burrows into your skin, leaving pimple-like burrows that itch.

For more information, visit


Lower-back/upper-leg pain caused by irritation of the sciatic nerve (a large nerve that extends from the lower back down into the legs). The cause of this irritation is often a herniated disk pressing on the nerve, but it can also be caused by inflammation or other irritants.


Scoliosis is a sideways curving of the spine.

For more information, visit


A disorder caused by a lack of vitamin C that causes bleeding in the gums, anemia, and bumpy skin.


An acute viral infection (caused by a re-activation of the chickenpox virus) that causes nerve inflammation, neuralgia, and blister-like vesicles along the affected nerve paths.

For more information, visit

Spurs, Bone

Outgrowths of bone (typically in the heel or sole of the feet) that cause inflammation of the surrounding tendons, making movement painful. Ice packs on the inflamed tendons can help reduce pain and swelling.

Staph Infections

Staph infections are any type of infection caused by the Staphylococcus bacteria. While skin infections caused by the staphylococcus bacteria are very common, and usually require no treatment, they can become very serious—especially when they occur in surgical wounds, or open bed sores.

For more information, visit

Strep Throat

Strep throat is an infection caused by the streptococcal bacteria in the throat that causes a sore throat and fever.

For more information, visit


Tendonitis is the painful inflammation of the tendons (the tissue that connects muscles to bones) due to injury, overuse, or disease.


Thrush is an overgrowth of the fungus Candida (found normally on the skin and mucus membranes) caused by an imbalance in the environment in the mouth or throat that results in white patches in the mouth and potentially painful swallowing.

For more information, visit


Tinnitus, or a ringing in the ears, is caused by many different things, including: ear damage from loud noises, excess ear fluid, infections, diseases, and some medications.


TMJ (temporomandibular joint) disorder or syndrome is characterized by chronic pain in the joint connecting the jawbone to the skull and in the surrounding area. This pain is often caused by clenching or grinding the jaw due to stress or habit. It can also be caused by an injury to the joint or arthritis.


Inflammation of the tonsils due to infection or disease.


Tuberculosis is a disease caused by bacteria that can attack the lungs, resulting in a severe, bloody cough, chest pains, fever, chills, and loss of appetite.

For more information, visit


An abnormal growth of tissue. A tumor may be either cancerous (malignant) or non-cancerous (benign).


Typhoid is a bacterial disease that causes a high, sustained fever, weakness, stomach pains, headache, and loss of appetite. If untreated, the fever may last for weeks, or even months, and could result in death.

For more information, visit


Any agent that causes the blood vessel walls to relax, increasing the diameter of the blood vessel and allowing more blood to flow through.


A feeling that the environment is spinning around you, or that you are spinning. Typically caused by a problem in the inner ear.


A small outgrowth of skin caused by a virus.


Over stretching or tearing the muscles and tendons in the neck and head due to a collision pushing the body in one direction, while the head’s tendency is to remain in the same place, causing the head to quickly rock in the opposite direction the body is going.

Whooping Cough

Whooping cough (or pertussis) is caused by Bordetella pertussis bacteria. This highly contagious disease causes severe bouts of coughing, whooping, and vomiting; and in small children and infants can lead to seizure, apnea (closure of airways), pneumonia, malnutrition, and other serious complications.

For more information, visit

Sources (besides those listed above):

Center for Disease Control (

Environmental Protection Agency (

Medline Plus Medical Encyclopedia (

(Opens a printer friendly page for this article in a new window.)