Illustration of amoeba
- 1 pseudopodium
- 2 nucleus
- 3 contractile vacuole
- 4 food vacuole
variants
or less commonly ameba
plural amoebas or amoebae also amebas or amebae
ə-ˈmē-(ˌ)bē 
: any of a large genus (Amoeba) of naked rhizopod protozoans with lobed and never anastomosing pseudopodia, without permanent organelles or supporting structures, and of wide distribution in fresh and salt water and moist terrestrial environments
broadly
: a naked rhizopod or other amoeboid protozoan
amoebic
adjective
or less commonly amebic
ə-ˈmē-bik
Examples of amoeba in a Sentence
Recent Examples on the Web
Naegleria fowleri is a type of amoeba that thrives in warm freshwater lakes, rivers and hot springs.
—
Melina Khan, USA Today, 23 July 2025
On July 22, the hospital confirmed the patient died from the infection
A child in South Carolina has died after being infected with a rare brain-eating amoeba, state health officials confirmed.
—Vanessa Etienne, People.com, 23 July 2025
Perhaps the scariest—but also the rarest, with fewer than 10 cases in the U.S. annually—is Naegleria fowleri (N. fowleri), an amoeba that can cause a fatal brain infection.
—Julia Ries, Health, 17 June 2025
Treatment of brain-eating amoebas When a patient has been diagnosed with a brain-eating amoeba, treatment usually includes a variety of antifungal medications, as well as antibiotics like rifampin and azithromycin, according to Lundstrom.
—Melissa Rudy, FOXNews.com, 6 June 2025
See All Example Sentences for amoeba
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Melina Khan, USA Today, 23 July 2025
On July 22, the hospital confirmed the patient died from the infection
A child in South Carolina has died after being infected with a rare brain-eating amoeba, state health officials confirmed.
—Vanessa Etienne, People.com, 23 July 2025
Perhaps the scariest—but also the rarest, with fewer than 10 cases in the U.S. annually—is Naegleria fowleri (N. fowleri), an amoeba that can cause a fatal brain infection.
—Julia Ries, Health, 17 June 2025
Treatment of brain-eating amoebas When a patient has been diagnosed with a brain-eating amoeba, treatment usually includes a variety of antifungal medications, as well as antibiotics like rifampin and azithromycin, according to Lundstrom.
—Melissa Rudy, FOXNews.com, 6 June 2025
See All Example Sentences for amoeba
Cite this Entry
“Amoeba.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/amoeba. Accessed 29 Jul. 2025.
Copy CitationKids Definition
amoeba
noun
amoe·ba
variants
also ameba
ə-ˈmē-bə
plural amoebas or amoebae
-(ˌ)bē
: any of a large genus of protozoans that have no permanent cell organs or structures, that change shape to form temporary lobes for moving and taking in food, and that are widespread in fresh and salt water and in moist soils
Medical Definition
amoeba
noun
amoe·ba
ə-ˈmē-bə
1
capitalized
: a large genus of naked rhizopod protozoans that have lobed and never anastomosing pseudopodia and are widely distributed in fresh and salt water and moist terrestrial environments
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