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[proh-tuh-zoh-uh] /ˌproʊ təˈzoʊ ə/
a major grouping or superphylum of the kingdom Protista, comprising the protozoans.
Origin of Protozoa
From New Latin, dating back to 1825-35; See origin at proto-, -zoa


[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.
First recorded in 1860-65; Protozo(a) + -an


[proh-tuh-zoh-on, -uh n] /ˌproʊ təˈzoʊ ɒn, -ən/
noun, plural protozoa
[proh-tuh-zoh-uh] /ˌproʊ təˈzoʊ ə/ (Show IPA)
singular of Protozoa Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2017.
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British Dictionary definitions for Protozoa


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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Word Origin and History for Protozoa

1828, from Modern Latin Protozoa, coined 1818 by German zoologist Georg August Goldfuss (1782-1848) from Greek protos "first" (see proto-) + zoia, plural of zoion "animal" (see zoo). Originally including sponges and corals; current sense is from 1845. Related: Protozoon (aingular); Protozoan.

Online Etymology Dictionary, © 2010 Douglas Harper
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Protozoa in Medicine

protozoa pro·to·zo·a (prō'tə-zō'ə)
Plural of protozoan.

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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Protozoa 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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Protozoa in Culture
protozoa [(proh-tuh-zoh-uh)]

Single-celled animals, such as amoebas, that are the most primitive form of animal life. In modern biology, they are classified in the kingdom of Protoctista rather than in the animal kingdom. (See Linnean classification.)

Note: Some protozoa are parasites and may be pathogenic, causing diseases such as malaria and dysentery.
The American Heritage® New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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