- plural of alga.
algae
Americanplural noun
-
alga
singular
plural noun
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Algae supply a considerable part of the world's oxygen.
The most familiar algae are the greenish scum that collects in still water.
Other Word Forms
Etymology
Origin of algae
First recorded in 1790–1800; from New Latin, plural of Latin alga “seaweed”
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How does algae compare to similar and commonly confused words? Explore the most common comparisons:
Explanation
Ever walk in the ocean and feel your feet slipping and sliding along the rocks? That slimy green stuff under your feet is algae, a nonflowering plant that grows in the water and has no stems, roots, or leaves. Algae is actually the plural form of the word alga, which in Latin means, you guessed it: "seaweed." Algae isn't just something gross looking floating on the water. It's actually important in aquatic ecology because the tiny organisms that live suspended in algae are the food base for most marine food chains.
Vocabulary lists containing algae
Something's Fishy: A Fresh Catch of Aquatic Words
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Ecology - Middle School
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Ecology - High School
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Example Sentences
Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.
See Examples For:
During droughts, algae blooms have turned waterways bright green.
From Los Angeles Times ● Oct. 30, 2026
The researchers examined concentrations of a biomarker known as IP25, which is produced by algae associated with sea ice.
From Science Daily ● Oct. 26, 2026
The five-term senator said the categories of products receiving exemptions include corrugated paper cartons, plastic boxes, plastic bags, refrigeration and freezing equipment, packing and wrapping machinery, and seaweed and algae products.
From MarketWatch ● Oct. 23, 2026
"Whenever the bad algae grows more, because of the nutrients in the lakes, it will release the various toxins that are very harmful for humans."
From BBC ● Oct. 23, 2026
When she waded into the swamp, the reeds twisted themselves into a boat, and she climbed aboard, floating across the deep red of the algae coating the water.
From "The Girl Who Drank the Moon" by Kelly Barnhill
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Moreover, the alga cannot easily move away from the light like animals and humans can.
From Science Daily ● Nov. 18, 2024
In this study, pyrenoid-associated proteins in a marine chlorarachniophyte alga were identified through a proteomic approach.
From Science Daily ● Mar. 1, 2024
Blue-green algae is not actually an alga but rather a type of bacteria called cyanobacteria.
From BBC ● Jul. 10, 2023
Myriam Valero, a population geneticist at CNRS, the French national research agency, has been studying the genetics of the red alga Gracilaria gracilis for many years in the tidepools of Europe.
From Science Magazine ● Jul. 27, 2022
She is curious; she wants to know the difference between an alga and a lichen, a Diplodon char- ruanus and a Diplodon delodontus.
From "All the Light We Cannot See" by Anthony Doerr
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