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 (prō′tə-zō′ən) also pro·to·zo·on (-ŏn′)
n. pl. pro·to·zo·ans or pro·to·zo·a (-zō′ə) also pro·to·zo·ons
Any of numerous chiefly single-celled eukaryotic organisms, most of which move about freely and ingest food, including the amoebas, ciliates, flagellates, and apicomplexans. Protozoans along with certain algae, oomycetes, and some other groups make up the protists.

[From New Latin Prōtozōa, former subkingdom name : proto- + -zōa, pl. of -zōon, -zoon.]

pro′to·zo′an, pro′to·zo′al, pro′to·zo′ic adj.
American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.protozoa - in some classifications considered a superphylum or a subkingdomProtozoa - in some classifications considered a superphylum or a subkingdom; comprises flagellates; ciliates; sporozoans; amoebas; foraminifers
kingdom Protoctista, Protoctista - in most modern classifications, replacement for the Protista; includes: Protozoa; Euglenophyta; Chlorophyta; Cryptophyta; Heterokontophyta; Rhodophyta; unicellular protists and their descendant multicellular organisms: regarded as distinct from plants and animals
protozoan, protozoon - any of diverse minute acellular or unicellular organisms usually nonphotosynthetic
class Sarcodina, Sarcodina - characterized by the formation of pseudopods for locomotion and taking food: Actinopoda; Rhizopoda
Ciliata, Ciliophora, class Ciliata, class Ciliophora - class of protozoa having cilia or hairlike appendages on part or all of the surface during some part of the life cycle
class Sporozoa, Sporozoa - strictly parasitic protozoans that are usually immobile; includes plasmodia and coccidia and piroplasms and malaria parasites
phylum - (biology) the major taxonomic group of animals and plants; contains classes
Based on WordNet 3.0, Farlex clipart collection. © 2003-2012 Princeton University, Farlex Inc.
References in classic literature ?
In attempting to understand the elements out of which mental phenomena are compounded, it is of the greatest importance to remember that from the protozoa to man there is nowhere a very wide gap either in structure or in behaviour.
Transgenic ciliated protozoa of the invention can serve as live vaccines.
Common waterborne infections that back-country and international travelers may contract include bacterial diarrhea, viruses, protozoa (such as Giardia and Cryptosporidium), and parasites (such as schistosoma).
Parasites found on the exterior of the host are called ectoparasites (such as lice or fleas), whereas those found inside the host are called endoparasites (such as worms, amebae, and malaria protozoa) (Figure 6-1A and B).
Hooke's folio, which was launched online yesterday at the Royal Society in London, reveals his rivalry with another of the founding fathers of British science, Sir Isaac Newton, and contains the first recorded siting of protozoa. The text was saved from auction and bought for pounds 950,000 with support from 150 donors and grants from the Wellcome Trust, the UK's largest biomedical research charity.
The life cycle of these nasty protozoa is complicated.
Part one is filled with information about the soil-food web from bacteria, fungi, algae, and protozoa to earthworms, gastropods, and mammals; part two describes in detail how to apply the soil-food web effectively in one's gardening, with the note that no one ever had to fertilize an old-growth forest.
The Pathogens link leads to organism-specific sequencing information for more than 100 bacteria, fungi, protozoa, helminths, vectors, and plasmids, as well as a variety of computational toots.
Lower termites have symbiotic associations with protozoa in their gut, which enables them to digest cellulose.