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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 17, 2026

apical pulse

AP-ih-kul puls · noun

The heartbeat counted by listening with a stethoscope over the tip (apex) of the heart, on the left side of the chest.

Full entry
depressionA mood disorder of lasting sadness or loss of interest that affects thinking, sleep, appetite and daily life.
depressive disorderA mental health condition of lasting low mood or loss of interest that gets in the way of daily life.
dermatitisInflammation of the skin.
dermisThe thick layer of skin under the epidermis that holds blood vessels, nerves, hair roots and glands.
detemirA long-acting (basal) insulin given under the skin once or twice a day.
developmentalRelating to how a person grows and changes in body, mind and behavior across their life.
developmental disabilityA lifelong condition, starting in childhood, that limits a person's physical, learning, language or behavior skills.
developmental dysplasia of the hipA condition in which the hip socket is too shallow to hold the top of the thigh bone firmly in place.
developmental milestoneA skill that most children can do by a certain age, such as smiling, sitting, walking or saying words.
developmental stageA period of life, such as infancy or adolescence, with its own typical abilities, needs and tasks.
dexamethasoneA strong, long-acting corticosteroid drug that reduces inflammation and calms the immune system.
dextroamphetamineA central nervous system stimulant used for attention-deficit/hyperactivity disorder and narcolepsy.
dextromethorphanA non-opioid cough suppressant sold without a prescription in many cough and cold products.
dextroseA form of glucose sugar given by mouth or IV for energy or to raise a low blood sugar.
dextrose 5% in waterAn IV fluid of 5 grams of glucose in every 100 mL of water, written D5W.
di-A word beginning that means two or twice.
dia-A word beginning that means through, across, apart or completely.
diabetes insipidusA disorder of antidiuretic hormone: the body makes too little of it, or the kidneys do not respond to it.
diabetes mellitusA long-term disease in which blood glucose stays high because the body makes too little insulin or cannot use it well.
diabetic ketoacidosisA state of high blood glucose, ketones in the blood and acidic blood, caused by a lack of insulin.
diabetic retinopathyDamage to the small blood vessels of the retina caused by diabetes.
diagnosisThe naming of a disease or problem after the facts about a person have been gathered and studied.
diagnostic testA test that gives information to find or rule out a disease, or to see how a disease or treatment is going.
dialysateThe fluid used in dialysis to pull waste products and extra fluid out of the blood.
dialysisA treatment that removes wastes and extra fluid from the blood when the kidneys can no longer do it.
diaper dermatitisIrritation and redness of the skin in the area covered by a diaper.
diaphoresisHeavy sweating, more than expected for the temperature or activity.
diaphragmThe dome-shaped sheet of muscle under the lungs that is the main muscle of breathing; also the flat side of a stethoscope.
diarrheaLoose or watery stools, usually three or more times a day or more often than normal for the person.
diastoleThe part of each heartbeat when the heart muscle relaxes and the chambers fill with blood.
diastolicRelating to diastole, the part of each heartbeat when the heart muscle relaxes and its chambers fill with blood.
diazepamA long-acting benzodiazepine drug used for anxiety, muscle spasm, alcohol withdrawal and seizures.
dietaryHaving to do with the food and drink a person takes in.
diethylstilbestrolA man-made estrogen, once given in pregnancy to prevent miscarriage, no longer used in the US.
dietitianA health professional trained in food and nutrition who assesses a person's nutrition needs and plans their diet.
diffusionThe movement of particles from an area where they are more concentrated to one where they are less concentrated.
digestionThe process of breaking food down into small parts the body can absorb and use.
digestiveHaving to do with digestion, the breakdown of food into parts the body can absorb.
digestive systemThe organs that take in food, break it down, absorb nutrients and get rid of waste.
digoxinA drug that makes the heart beat more strongly and more slowly.
digoxin levelA blood test that measures how much of the heart drug digoxin is in the blood.
dilateTo widen or open up.
dilationThe widening or opening up of a body part, such as the cervix during labor, the pupils or a blood vessel.
dilatorAn instrument used to stretch or widen an opening, canal or passage in the body.
dilemmaA hard choice between two or more options, where each one has a real drawback.
diltiazemA calcium channel blocker that slows the heart rate and relaxes blood vessels, given by mouth or IV.
dimenhydrinateAn antihistamine taken to prevent and treat motion sickness, nausea and vertigo.
dimercaprolAn injected chelating drug that binds heavy metals such as arsenic, mercury, gold and lead so the body can remove them.
diminished breath soundBreath sounds that are quieter or harder to hear than normal when listening to the lungs with a stethoscope.
diphenhydramineA first-generation antihistamine used for allergies, itching, motion sickness, sleep and some drug reactions.