pro·​to·​zo·​an | \ ˌprō-tə-ˈzō-ən How to pronounce protozoan (audio) \

Definition of protozoan

: any of a phylum or subkingdom (Protozoa) of chiefly motile and heterotrophic unicellular protists (such as amoebas, trypanosomes, sporozoans, and paramecia) that are represented in almost every kind of habitat and include some pathogenic parasites of humans and domestic animals

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Other Words from protozoan

protozoan adjective

Examples of protozoan in a Sentence

Recent Examples on the Web The protozoan parasite is transmitted through the bite of a female mosquito. Peter Fimrite,, "If you have this blood type, studies show you’re at higher risk for the coronavirus," 9 July 2020 The disease is caused by the protozoan parasite Plasmodium, which often grows in the liver before infecting red blood cells. Uwagbale Edward-ekpu, Quartz Africa, "Americans are turning to one of Africa’s most common prescribed drugs to battle coronavirus," 21 Mar. 2020 With a resolution of 3 micron and a field of view of around one millimeter, this lens, which is packaged in red, allows the user to see cells and microorganisms like protozoans and water bears. Courtney Linder, Popular Mechanics, "If You've Ever Wanted a Smartphone Microscope, Now's Your Chance," 22 Nov. 2019 The same holds true for many fungi, algae and protozoans today. Quanta Magazine, "Why Nature Prefers Couples, Even for Yeast," 17 July 2018 In fact, LifeStraw claims its contraption can remove 99.9999% of waterborne bacteria, 99.9% of waterborne protozoan parasites. Kelsey Mulvey, Popular Mechanics, "Turn Any Stream Into Clean Drinking Water With The LifeStraw for Just $15," 2 Mar. 2020 Davis thinks a protozoan parasite that infects monarchs could be on the rise. Gabriel Popkin, Scientific American, "What Is Really Killing Monarch Butterflies?," 1 Mar. 2020 The rest belong to micro-organisms — bacteria, fungi, protozoans and viruses — that are on and inside you. Fortune, "Why Washing Your Hands Too Much Could Make You Sick," 12 June 2018 The National Parasite Collection, which includes millions of specimens of lice, mites, nematodes, protozoans, ticks and other critters, arrived from the Agriculture Department in 2014. Daniel Nasaw, WSJ, "Tight at the Museum: A Smithsonian Struggles to Find Space for the World’s Stuff," 7 June 2018

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

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First Known Use of protozoan

circa 1864, in the meaning defined above

History and Etymology for protozoan

New Latin Protozoa, from prot- + -zoa

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Time Traveler for protozoan

Time Traveler

The first known use of protozoan was circa 1864

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Last Updated

13 Jul 2020

Cite this Entry

“Protozoan.” Dictionary, Merriam-Webster, Accessed 12 Aug. 2020.

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More Definitions for protozoan


How to pronounce protozoan (audio)

English Language Learners Definition of protozoan

: a tiny organism whose body is a single cell


pro·​to·​zo·​an | \ ˌprō-tə-ˈzō-ən How to pronounce protozoan (audio) \

Kids Definition of protozoan

: a single-celled organism (as an amoeba or paramecium) that is a protist and is capable of movement


pro·​to·​zo·​an | \ -ˈzō-ən How to pronounce protozoan (audio) \

Medical Definition of protozoan

 (Entry 1 of 2)

: any protist of the phylum or subkingdom Protozoa



Medical Definition of protozoan (Entry 2 of 2)

: of or relating to the phylum or subkingdom Protozoa

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Spanish Central: Translation of protozoan

Nglish: Translation of protozoan for Spanish Speakers Encyclopedia article about protozoan

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