antibiotic

American  

[an-ti-bahy-ot-ik, -bee-, an-tee-, -tahy-] / ˌæn tɪ baɪˈɒt ɪk, -bi-, ˌæn ti-, -taɪ- /

noun

• antibiotics
  plural

1. any of a large group of chemical substances, as penicillin or streptomycin, produced by various microorganisms and fungi, having the capacity in dilute solutions to inhibit the growth of or to destroy bacteria and other microorganisms, used chiefly in the treatment of infectious diseases.

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adjective

1. of or involving antibiotics.

antibiotic British  

/ ˌæntɪbaɪˈɒtɪk /

noun

1. any of various chemical substances, such as penicillin, streptomycin, chloramphenicol, and tetracycline, produced by various microorganisms, esp fungi, or made synthetically and capable of destroying or inhibiting the growth of microorganisms, esp bacteria

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adjective

1. of or relating to antibiotics

antibiotic Scientific  

/ ăn′tĭ-bī-ŏt′ĭk /

1. A substance, such as penicillin, that is capable of destroying or weakening certain microorganisms, especially bacteria or fungi, that cause infections or infectious diseases. Antibiotics are usually produced by or synthesized from other microorganisms, such as molds. They inhibit pathogens by interfering with essential intracellular processes, including the synthesis of bacterial proteins. Antibiotics do not kill viruses and are not effective in treating viral infections.

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1. Relating to antibiotics.

2. Relating to antibiosis.

antibiotic Cultural  

1. A substance that destroys or inhibits the growth of microorganisms and is therefore used to treat some infections. One of the most familiar antibiotics is penicillin.

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Discover More

Microorganisms that are initially treatable with antibiotics may evolve resistance as the more susceptible members of the population are killed off. (See resistance to antibiotics.)

Other Word Forms

Derived Forms

• antibiotically
  adverb

Inflected Forms

Nouns

• antibiotics
  plural

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Etymology

Origin of antibiotic

1855–60, for an earlier sense; anti- + biotic

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Explanation

An antibiotic is a substance used to kill bacteria. If you're coughing up green stuff, the doctor might give you an antibiotic to fight the infection. Since the prefix anti- means fighting, opposing, or killing, and bios is the Greek word for "life," antibiotic literally means life-killing. But doctors prescribe them primarily to kill the bacteria responsible for infections in the body. (A virus, on the other hand, cannot be treated with an antibiotic, so doctors are always making a distinction between a virus and a bacterial infection.) You can also use antibiotic as an adjective. Some plants have natural antibiotic effects when eaten.

Example Sentences

See Examples For:

antibiotic antibiotics

"You end up hunting for a decent length of antibiotic courses that will give you some relief," she said.

From BBC ● Oct. 13, 2026

"You're altering the microbiome of your gut, and perhaps creating antibiotic resistant bacteria in your body that will fight off the drug therapy the next time you really need it," he said.

From Barron's ● Oct. 8, 2026

Patients with blood cancers who receive stem cell transplants are often hospitalized for several weeks while undergoing chemotherapy and antibiotic treatment.

From Science Daily ● Oct. 7, 2026

The revived proteins could provide scientists with new ideas for treating antibiotic resistant infections, which have become a major global health challenge.

From Science Daily ● Sep. 28, 2026

Usually, a ten-day antibiotic treatment alleviates the symptoms, or a fast in-office medical procedure can release the pressure.

From "Endgame" by Frank Brady

This includes new antibiotics and antivirals, as well as antifungals—anti-anything that could be used against us.

From The Wall Street Journal ● Oct. 14, 2026

Chronic UTIs are infections where symptoms do not go away, and do not clear with a short course of antibiotics.

From BBC ● Oct. 13, 2026

"Our findings show that it might be worthwhile to examine targeted antibiotics from ethnographic contexts - or, as in this case, from prehistoric contexts - in greater depth," concludes Siemssen.

From Science Daily ● Oct. 11, 2026

Additional allegations included forced labor on fishing vessels and reliance on harmful pesticides and antibiotics.

From Los Angeles Times ● Oct. 9, 2026

On Monday morning I was able to leave at last, with a bottle of antibiotics and an arm full of pinpricks.

From "The Secret History" by Donna Tartt

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Related Words

• penicillin

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