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

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

The study focused on Klebsormidiophyceae, a class of green algae known for its ability to colonize diverse habitats worldwide.

From Science Daily • Jan. 23, 2024

It reaches the sea through a corridor of lush green algae on the edge of the beach.

From BBC • Jun. 15, 2023

I scrub out the green algae that clouds his bowl, and then refill the bowl.

From "Muffled" by Jennifer Gennari