pen·​i·​cil·​li·​um | \ ˌpe-nə-ˈsi-lē-əm How to pronounce penicillium (audio) \
plural penicillia\ ˌpe-​nə-​ˈsi-​lē-​ə How to pronounce penicillium (audio) \

Definition of penicillium

: any of a genus (Penicillium) of fungi (such as a blue mold) that are found chiefly on moist nonliving organic matter (such as decaying fruit) and have been grouped with the imperfect fungi but are now often placed with the ascomycetes

Examples of penicillium in a Sentence

Recent Examples on the Web This gives the penicillium enough air to extend its gorgeous greenish veins throughout the cheese. Joshua Levine, Smithsonian Magazine, 20 Nov. 2021 Although underappreciated at first, Fleming’s discovery proved monumental in the field of immunology—and primed the scientist to recognize the potential of the penicillium mold that dropped into his lab dish in 1928. Claudia Kalb, Scientific American, 27 Apr. 2021 Blue cheese, which has been ripened with cultures of the mold penicillium, includes varieties such as Stilton and Gorgonzola. Jenna Birch, Washington Post, 2 Sep. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'penicillium.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

First Known Use of penicillium

1867, in the meaning defined above

History and Etymology for penicillium

New Latin, from Latin penicillus

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Time Traveler for penicillium

Time Traveler

The first known use of penicillium was in 1867

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Dictionary Entries Near penicillium

penicillinic acid


Peniel Mission

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Cite this Entry

“Penicillium.” Dictionary, Merriam-Webster, Accessed 10 Aug. 2022.

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More Definitions for penicillium


pen·​i·​cil·​li·​um | \ ˌpen-ə-ˈsil-ē-əm How to pronounce penicillium (audio) \

Medical Definition of penicillium

1 capitalized : a genus of fungi (as the blue molds) that have been grouped with the imperfect fungi but are now often placed with the ascomycetes and that are found chiefly on moist nonliving organic matter (as decaying fruit), are characterized by the erect branching conidiophores ending in tufts of club-shaped cells from which conidia are formed in chains, and include molds useful in economic fermentation and the production of antibiotics
2 plural penicillia\ -​ē-​ə How to pronounce penicillium (audio) \ : any mold of the genus Penicillium

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