green algae

American  

plural noun

1. any grass-green, chiefly freshwater algae of the phylum Chlorophyta, often growing on wet rocks, damp wood, or on the surface of stagnant water.

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green algae British  

plural noun

1. the algae of the phylum Chlorophyta, which possess the green pigment chlorophyll. The group includes sea lettuce and spirogyra

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Etymology

Origin of green algae

First recorded in 1900–05

Example Sentences

"I hate any kind of pollution to be honest, there's blue and green algae here, there's bird flu, ducks and swans dying."

From BBC • Mar. 10, 2026

Now, because bright green algae keeps reappearing every year around this time, Toledo must always be prepared for such outbreaks.

From Salon • Aug. 16, 2025

There’s a faucet on the eastern end of the campground where water from the creek is piped, but upon my arrival, the trough where the water came out was covered in thick green algae.

From Los Angeles Times • May 13, 2025

A team of scientists led by the University of Göttingen has taken a deep dive into the evolutionary history of morphological complexity in streptophytes, which include land plants and many green algae.

From Science Daily • Jan. 23, 2024

It’s a small, shallow lake, with psychedelic swirls of green algae on top.

From "A Heart in a Body in the World" by Deb Caletti