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Definition of penicillin

penicillin

/ˌpɛnɪˈsɪlɪn/
pen · i · cil · lin
Plural:penicillins
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penicillin Lexical Profile

penicillin Game Scores & Validity

• noun

1

An antibiotic or group of antibiotics produced naturally by certain blue molds of the genus Penicillium or synthesized chemically, widely used to treat bacterial infections by inhibiting the formation of bacterial cell walls.

Example

"The doctor prescribed a ten-day course of penicillin to clear up the patient's severe strep throat."

Synonyms
View all synonyms for penicillin

• Rhymes for penicillin

• Nearby Words

penguin
penguin tetra
penholder
penicillin
penile
peninsula
peninsular

Word Origin & Etymology

Coined in 1929 by Scottish bacteriologist Alexander Fleming from the scientific genus name Penicillium (derived from Latin penicillus, meaning 'painter's brush', because the spore-bearing strands of the mold resemble a miniature brush) plus the chemical suffix -in.

Usage Trend

Historical frequency of usage in published text.

180019102020
Data source: Google Books Ngram Viewer

Cite this Entry

Wordmom. (2026). Definition of Penicillin. In Wordmom Dictionary. Retrieved Nov 5, 2026, from https://wordmom.com/dictionary/penicillin
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