amoeba

noun amoe·ba \ ə-ˈmē-bə \

variants: or less commonly ameba

|Updated on: 12 Jun 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

Although the scientists have only worked on amoeba-killing viruses, the research heightens concerns that pathogens infectious to humans will also emerge — outside of the laboratory — as permafrost thaws.

— bridget alex, Discover Magazine, "Something Stirs: What Will Happen as Permafrost Thaws?," 15 May 2018
Both reawakened in laboratory dishes and infected living amoebas.

— bridget alex, Discover Magazine, "Something Stirs: What Will Happen as Permafrost Thaws?," 15 May 2018
The story of an actress nipping at Beyoncé, as told to GQ by one Tiffany Haddish, has turned the internet in one, giant, amoeba-like detective.

— rebecca farley, refinery29.com, "American Crime Story: Who Bit Beyoncé," 28 Mar. 2018
The amoeba can infect a person when water goes up the nose and infections are rare, but almost always fatal.

— fred clasen-kelly, charlotteobserver, "Brain-eating amoeba killed this teen after rafting at Whitewater Center. Facility says it’s not to blame.," 14 Feb. 2018
The amoeba is typically found in lakes, rivers and hot springs and can enter the body through the nose, according to the U.S. Centers for Disease Control and Prevention.

— marco santana, OrlandoSentinel.com, "Sporting-goods giveaway honors memory of boy, 11, who died of amoeba-borne infection," 10 Dec. 2017
Mosquito infestations, shark attacks and amoeba that can crawl up your nose and eat your brain.

— scott maxwell, OrlandoSentinel.com, "Irma vs. Florida: The latest battle in our disaster-prone state," 11 Sep. 2017
The tactic, though effective, has earned her a reputation for hogging too much of the political spectrum; in a recent cartoon, the daily Berliner Zeitung depicted the Chancellor as a shapeless amoeba, methodically swallowing and digesting its prey.

— simon shuster, Time, "The Ad Guru Hired to Help Reshape Angela Merkel's Image," 14 June 2016
The same concentration that knocks out a person will anesthetize a sea slug or an amoeba, and will even paralyze a fern that normally curls up when touched, Dr. Shafer said.

— denise grady, New York Times, "Dr. Edmond Eger II, 86, Dies; Found Way to Make Anesthesia Safer," 20 Sep. 2017

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