prophylaxis
Americannoun
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Medicine/Medical.
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the preventing of disease.
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the prevention of a specific disease, as by studying the biological behavior, transmission, etc., of its causative agent and applying a series of measures against it.
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prophylactic treatment, as the cleaning of the teeth by a dentist or dental hygienist.
noun
Etymology
Origin of prophylaxis
1835–45; < New Latin < Greek pro- pro- 2 + phýlaxis a watching, guarding, equivalent to phylak- (base of phylássein to guard) + -sis -sis
Explanation
Prophylaxis refers to all the things people do to prevent disease. Prophylaxis is part of medicine. If you've ever heard of someone using prophylactics to prevent a disease — often a sexually transmitted disease — then you have a clue to the meaning of prophylaxis, which refers to the prevention of disease. Anything you do to stay healthy and keep illness at bay would be categorized as prophylaxis. Antibiotic prophylaxis refers to giving patients antibiotics to prevent a bacterial infection, instead of curing an infection that already exists.
Vocabulary lists containing prophylaxis
The Man Who Mistook His Wife for a Hat
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Cheaper by the Dozen
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
Merck currently has four HIV drug development programs including a once-daily oral treatment, two once-weekly oral treatments, and a once-monthly oral pre-exposure prophylaxis that’s meant to prevent HIV infection.
From Barron's • Feb. 25, 2026
I started off pretty skeptical about echinacea, but actually, I’m an author on studies showing that echinacea reduces antibiotic usage by about 70 percent in children if they use it as a prophylaxis.
From Slate • Oct. 8, 2025
It is hoped it will replace the current form of HIV preventative drug, know as PrEP, or pre-exposure prophylaxis, which is taken orally and also costs $40 per person each year.
From BBC • Sep. 24, 2025
That work has included ramping up HIV testing and PrEP, or preexposure prophylaxis, programs, as well as expanding care for transgender people living with the virus.
From Seattle Times • Sep. 10, 2023
She had no prophylaxis, unfortunately, for Death by Drowning.
From "The God of Small Things" by Arundhati Roy
Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.
