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[proh-tuh-zoh-uh n] /ˌproʊ təˈzoʊ ən/ Biology
noun, plural protozoans (especially collectively) protozoa
[proh-tuh-zoh-uh] /ˌproʊ təˈzoʊ ə/ (Show IPA)
any of a diverse group of eukaryotes, of the kingdom Protista, that are primarily unicellular, existing singly or aggregating into colonies, are usually nonphotosynthetic, and are often classified further into phyla according to their capacity for and means of motility, as by pseudopods, flagella, or cilia.
of, relating to, or characteristic of a protozoan.
1860-65; Protozo(a) + -an Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2015.
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Examples from the web for protozoan
  • The parasite, a single-cell organism known as a protozoan, goes through different phases in both its mosquito and human hosts.
  • From barnacles that hijack crabs to a protozoan that makes rodents cozy up to cats, parasites do a lot more than make you puke.
  • And there are major hurdles to be leaped if printless text publishing is going to move from protozoan to pachyderm.
  • The protozoan caused vomiting and watery diarrhea as well.
  • But once the fish had died, the remaining dinoflagellates started to circle the protozoan.
  • For example, spoiled food commonly contains toxoplasma, a protozoan parasite.
  • For animals, the evidence is pointing to a protozoan called a choanoflagellate.
  • If you suck a protozoan into an eyedropper it will find its way out.
British Dictionary definitions for protozoan


noun (pl) -zoa (-ˈzəʊə), -zoans
Also called protozoon (ˌprəʊtəˈzəʊɒn), (pl) -zoa. any of various minute unicellular organisms formerly regarded as invertebrates of the phylum Protozoa but now usually classified in certain phyla of protoctists. Protozoans include flagellates, ciliates, sporozoans, amoebas, and foraminifers
of or relating to protozoans
Word Origin
C19: via New Latin from Greek proto- + zoion animal
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
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protozoan in Medicine

protozoan pro·to·zo·an (prō'tə-zō'ən) or pro·to·zo·on (-ŏn')
n. pl. pro·to·zo·a (-zō'ə) or pro·to·zo·ans or pro·to·zo·a or pro·to·zo·ons
Any of a group of single-celled, usually microscopic, eukaryotic organisms, such as amoebas, ciliates, flagellates, and sporozoans.

pro'to·zo'an or pro'to·zo'al or pro'to·zo'ic adj.
The American Heritage® Stedman's Medical Dictionary
Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
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protozoan in Science
Plural protozoans or protozoa
Any of a large group of one-celled organisms (called protists) that live in water or as parasites. Many protozoans move about by means of appendages known as cilia or flagella. Protozoans include the amoebas, flagellates, foraminiferans, and ciliates. Their traditional classification as the subkingdom Protozoa is still used for convenience, but it is now known that protozoans represent several evolutionarily distinct groups. See more at protist.
The American Heritage® Science Dictionary
Copyright © 2002. Published by Houghton Mifflin. All rights reserved.
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