protozoan

noun

pro·​to·​zo·​an ˌprō-tə-ˈzō-ən 

: 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

protozoan adjective

Examples of protozoan in a Sentence

Recent Examples on the Web

Cause and Transmission Chagas disease, also known as American trypanosomiasis, is caused by the protozoan parasite Trypanosoma cruzi. —Matthew Binnicker, Forbes.com, 9 Sep. 2025

That legacy echoes in our every cell, yoking our fates to the vast unicellular realm, where creatures such as protozoans navigate threats, seek succor and sense their way from life to death. —Claire L. Evans, Quanta Magazine, 30 July 2025

This is why Darpa has tasked Rutgers with also engineering oysters resistant to dermo, a protozoan that’s dogged Atlantic oysters for decades. —Saqib Rahim, WIRED, 11 Oct. 2024

By Racz’s desk sits a cardboard box of parasite stuffed animals featuring cartoonish lice, ticks and the protozoan that causes Chagas disease. —Hannah Richter, Smithsonian Magazine, 31 July 2024

Word History

Etymology

New Latin Protozoa, from prot- + -zoa

First Known Use

circa 1864, in the meaning defined above

Rhymes for protozoan

• bryozoan
• metazoan
• coan
• kohen
• rohan
• rowan
• rowen
• minoan
• samoan

Kids Definition

protozoan

noun

pro·​to·​zo·​an ˌprōt-ə-ˈzō-ən 

: any of a phylum or group of microorganisms (as amoebas and paramecia) that are single-celled protists and have varied structure and physiology and often complicated life cycles

protozoan adjective

Medical Definition

protozoan

1 of 2 noun

pro·​to·​zo·​an -ˈzō-ən 

: any protist of the phylum or subkingdom Protozoa

protozoan

2 of 2 adjective

: of or relating to the phylum or subkingdom Protozoa