alga

noun

al·​ga ˈal-gə 

plural algae ˈal-(ˌ)jē  also algas

: a plant or plantlike organism of any of several phyla, divisions, or classes of chiefly aquatic usually chlorophyll-containing nonvascular organisms of polyphyletic origin that usually include the green, yellow-green, brown, and red algae in the eukaryotes and especially formerly the cyanobacteria in the prokaryotes

algal

ˈal-gəl 

adjective

Example Sentences

Recent Examples on the Web

The alga draws energy from sunlight and produces sugars, which the bacterium uses as fuel. —Ashley P. Taylor, Discover Magazine, 22 Sep. 2012

This is the first recorded example of an alga practicing an aquatic equivalent to pollination. —Jack Tamisiea, Scientific American, 28 July 2022

Yet here in this massive pool swirls more than a million liters of Nannochloropsis, a salt-loving alga that flourishes on the brackish water pumped from below. —Amy Nordrum, IEEE Spectrum, 30 May 2018

For example, since the 1960s, scientists have shown that a type of alga shows a daily cycle in its photosynthesis, even without a nucleus. —Ed Yong, Discover Magazine, 16 May 2012

In return, the bacterium processes nitrogen gas into ammonium, which the alga needs. —Ashley P. Taylor, Discover Magazine, 22 Sep. 2012

Namely, a safe place to hide from predators and a source of food in the form of small, single-celled alga that grow on red seaweed plants, reports Erik Stokstad for Science. —Sarah Kuta, Smithsonian Magazine, 29 July 2022

Giant kelp is the common name for Macrocystis pyrifera, a species of alga that grows into lush underwater forests along the coast of the northeastern Pacific Ocean, from Baja California north to southeastern Alaska. —Andrew Robinson, Scientific American, 21 July 2022

Lichens are actually two organisms working together: a fungus and either alga or cyanobacterium. —Corryn Wetzel, Smithsonian Magazine, 17 Feb. 2022

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Word History

Etymology

Latin, seaweed

First Known Use

1551, in the meaning defined above

Phrases Containing alga

• blue-green alga
• golden-brown alga
• brown alga
• green alga
• yellow-green alga
• red alga
• golden alga

• blue-green alga
• golden-brown alga
• brown alga
• green alga
• yellow-green alga
• red alga
• golden alga

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Kids Definition

alga

noun

al·​ga ˈal-gə 

plural algae ˈal-(ˌ)jē 

: any plant or plantlike organism (as a seaweed) that includes forms mostly growing in water, lacking a system of vessels for carrying fluids, and often having chlorophyll masked by brown or red coloring matter

algal

ˈal-gəl 

adjective

Medical Definition

alga

noun

al·​ga ˈal-gə 

plural algae ˈal-(ˌ)jē  also algas

: a plant or plantlike organism of any of several phyla, divisions, or classes of chiefly aquatic usually chlorophyll-containing nonvascular organisms of polyphyletic origin that usually include the green, yellow-green, brown, and red algae in the eukaryotes and especially formerly included the cyanobacteria in the prokaryotes

algal

-gəl 

adjective