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Medical terminology
Plain-language definitions of core medical terms. These are general explanations, not clinical guidance.
- acute
- Coming on quickly and usually lasting a short time; the opposite of chronic.
- benign
- Not cancerous. A benign growth does not invade nearby tissue or spread to other parts of the body.
- chronic
- Lasting a long time or coming back repeatedly; the opposite of acute.
- contraindication
- A condition or situation that makes a particular treatment, medicine or procedure inadvisable because it could cause harm.
- diagnosis
- The identification of a disease or condition from its signs, symptoms and test results.
- differential diagnosis
- The list of conditions that could explain a person's symptoms, which clinicians narrow down as evidence arrives.
- edema
- Swelling caused by fluid collecting in body tissues, often noticed in the legs, ankles or lungs.
- efficacy
- How well a treatment works under ideal, controlled conditions, such as in a clinical trial. Distinct from effectiveness, which is how well it works in everyday care.
- etiology
- The cause or set of causes of a disease or condition.
- hypertension
- High blood pressure: the pressure of blood against artery walls is persistently too high.
- incidence
- The number of new cases of a disease that appear in a population during a defined period.
- inflammation
- The body's protective response to injury or infection, marked by redness, heat, swelling and pain. Helpful in the short term; harmful when it persists.
- malignant
- Cancerous. A malignant growth can invade nearby tissue and spread to other parts of the body.
- morbidity
- The state of having a disease or condition, or the amount of illness in a population.
- mortality
- Death, or the number of deaths in a population during a defined period.
- palliative
- Care focused on relieving symptoms and improving quality of life rather than curing the underlying disease.
- placebo
- An inactive substance or procedure given as if it were a treatment, used in trials to measure the true effect of the real treatment.
- prevalence
- The total number of people in a population who have a disease at a given time, new and existing cases together.
- prognosis
- The likely course and outcome of a disease for a person or group, including chances of recovery or progression.
- prophylaxis
- A measure taken to prevent disease before it occurs, such as vaccination or preventive medication.
- remission
- A period during which the signs and symptoms of a disease are reduced or absent; it does not necessarily mean the disease is cured.
- screening
- Testing people who have no symptoms to find a disease early, when treatment works best.
- symptom
- Something a person experiences that may indicate illness, such as pain or fatigue. Distinct from a sign, which a clinician observes or measures.
- syndrome
- A recognized collection of signs and symptoms that tend to occur together and characterize a condition.