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Nursing and medical dictionary

Nursing and medical terms in plain words: what each one means, how to say it, the word parts it is built from, and why it matters at the bedside.

Word of the day · Oct 18, 2026

Mallory-Weiss tear

MAL-er-ee WYS tair · noun

A tear in the lining where the esophagus meets the stomach.

Full entry
malignant hyperthermiaA rare inherited reaction to certain general anesthesia drugs in which the muscles' metabolism speeds up out of control.
Mallory-Weiss tearA tear in the lining where the esophagus meets the stomach.
malnutritionPoor nutrition from too little, too much or the wrong balance of nutrients.
malpracticeNegligence by a professional, such as a nurse or doctor, that harms a client.
mamm/oA word root that means breast; mast/o means the same.
mammogramAn x-ray picture of the breast, used to screen for and look into breast cancer.
mandatory reportingA legal duty to report certain things, such as suspected abuse or some diseases, to the proper authorities.
mandibleThe lower jawbone, the only bone of the skull that moves.
maniaA period of unusually high energy, mood and activity that is clearly different from the person's usual self.
mannitolAn osmotic diuretic, given by IV, that draws water out of tissues into the blood so the kidneys can remove it.
markerSomething that can be measured, such as a substance in the blood, that shows a disease or body process is present.
marrowThe soft tissue inside bones; red marrow makes blood cells and yellow marrow stores fat.
maskA covering for the nose and mouth, worn to block germs or to deliver oxygen.
Maslow hierarchy of needsA theory that ranks human needs in five levels, from basic body needs at the bottom to self-fulfillment at the top.
mass casualty triageSorting many injured people quickly by need when there are more victims than staff and supplies can treat at once.
massageRubbing, pressing or kneading the body's soft tissues to relax muscles, ease pain or improve blood flow.
mast cellAn immune cell in the tissues that releases histamine and other chemicals during allergic reactions and inflammation.
mastectomySurgery to remove all or part of a breast.
master of science in nursingA graduate degree in nursing, earned after a bachelor's degree, that prepares nurses for advanced or specialized roles.
mastitisInflammation of the breast tissue, often with infection, most common in people who are breastfeeding.
maternalHaving to do with a mother, or with a woman during pregnancy, birth and the weeks after.
maturationThe process of becoming fully grown or developed.
Mayo standA small tray on an adjustable stand placed over or beside the patient during surgery to hold the instruments used most often.
McBurney pointA spot on the lower right abdomen about one-third of the way from the front of the hip bone to the navel.
mcgMicrogram: one millionth of a gram, or one thousandth of a milligram.
McRoberts maneuverPulling a laboring client's legs back sharply so the thighs press against the abdomen, to widen the pelvis during birth.
mean arterial pressureThe average pressure in the arteries over one heartbeat, used as a measure of how well blood reaches the organs.
mean corpuscular volumeThe average size of a person's red blood cells, reported as part of a complete blood count.
measlesA very contagious illness caused by the measles virus; also called rubeola.
meatusAn opening or passage in the body, such as the urinary opening or the ear canal.
mebendazoleA chewable drug that kills intestinal worms such as pinworms, roundworms and hookworms.
mechanical liftA device with a sling that lifts and moves a client who cannot bear weight, such as from bed to chair.
mechanical ventilationBreathing support from a machine, a ventilator, that pushes air into the lungs through a tube or a mask.
mechanism of actionHow a drug works in the body: the exact process by which it produces its effect.
meconiumA newborn's first stools: thick, sticky and dark green to black.
medialToward the middle line of the body.
medical asepsisClean technique: practices that lower the number of germs and stop them spreading from one person or object to another.
medical diagnosisThe name of a disease or condition, given by a physician or other provider, that explains a client's signs and symptoms.
medical examinerA doctor, appointed by the government, who investigates deaths that are sudden, unexpected, violent or unexplained.
medical historyA record of a person's past and present health, illnesses, surgeries, medicines, allergies and family health.
medical interpreterA trained person who changes spoken or signed words from one language to another so clients and health care workers understand each other.
medical recordThe legal record of a client's health history, care, tests and treatment, also called the chart.
medical-surgical unitA hospital unit that cares for adults with many kinds of illness and adults recovering from surgery.
medication administration recordThe part of a client's record that lists every ordered drug, dose, route and time, where nurses record each dose given.
medication errorA preventable mistake at any step of prescribing, preparing, giving or monitoring a medicine, whether or not it causes harm.
medication reconciliationComparing a client's full list of current medicines with new orders at each change in care, to find and fix differences.
meditationA practice of focusing the mind, such as on the breath, a word or an image, to calm thoughts and reduce stress.
medroxyprogesteroneA progestin hormone given as a birth control injection every 3 months, or as tablets for menstrual problems.
medullaThe inner part of an organ; most often the medulla oblongata, the lowest part of the brainstem.
megal/oA word part that means large or enlarged.