amoeba

noun amoe·ba \ ə-ˈmē-bə \

variants: or less commonly ameba

|Updated on: 21 Aug 2018

Definition of amoeba

plural amoebas or amoebae play \-(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

or less commonly amebic \-bik\ adjective

See amoeba defined for English-language learners

See amoeba defined for kids

Recent Examples of amoeba from the Web

Tragically, Minnesota has seen two fatalities in children caused from a waterborne amoeba that enters the nose and attacks the brain.

— glenn howatt, chicagotribune.com, "Swimming pools, hot tubs are more likely than lakes to make you sick, studies find," 11 July 2018
Tragically, Minnesota has seen two fatalities in children caused from a waterborne amoeba that enters the nose and attacks the brain.

— glenn howatt, chicagotribune.com, "Swimming pools, hot tubs are more likely than lakes to make you sick, studies find," 11 July 2018
Primary amebic meningoencephalitis, the disease caused by the amoeba, is almost always fatal, according to the CDC.

— brittney mcnamara, Teen Vogue, "What to Know About Brain-Eating Amoebas," 14 June 2018
Long mistaken for fungi, they are now classed as a type of amoeba.

— katia moskvitch, WIRED, "Slime Molds Remember—But Do They Learn?," 14 July 2018
Tragically, Minnesota has seen two fatalities in children caused from a waterborne amoeba that enters the nose and attacks the brain.

— glenn howatt, chicagotribune.com, "Swimming pools, hot tubs are more likely than lakes to make you sick, studies find," 11 July 2018
Tragically, Minnesota has seen two fatalities in children caused from a waterborne amoeba that enters the nose and attacks the brain.

— glenn howatt, ajc, "Swimming pools, hot tubs are more likely than lakes to make you sick, studies find," 9 July 2018
The episode's group date — awkward, amoeba-like dates — centered on a debate.

— rebecca farley, refinery29.com, "The Bachelorette Wants To Have Its Cake & Be Political, Too," 3 July 2018
That’s where the little amoeba passes through to the skull cavity and eats your brain.

— marc peruzzi, Outside Online, "19 Lessons I Learned from Extreme Sports Pros," 25 June 2018

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'amoeba.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

Illustration of amoeba

Origin and Etymology of amoeba

New Latin, genus name, from Greek amoibē change, from ameibein to change — more at migrate

NEW! Time Traveler

First Known Use: 1822

in the meaning defined above

See Words from the same year

AMOEBA Defined for English Language Learners

amoeba

noun

Definition of amoeba for English Language Learners

: a tiny living thing that consists of a single cell

AMOEBA Defined for Kids

amoeba

noun amoe·ba \ ə-ˈmē-bə \

Definition of amoeba for Students

plural amoebas or amoebae \-bē\

: a tiny water animal that is a single cell which flows about and takes in food

Medical Dictionary

amoeba

noun amoe·ba \ ə-ˈmē-bə \

medical Definition of amoeba

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

2 also ameba