Showing results for "algae"

• plural of alga.

algae

American  

[al-jee] / ˈæl dʒi /

plural noun

alga singular

1. Microbiology. any of numerous groups of chlorophyll-containing, mainly aquatic, eukaryotic organisms ranging from microscopic single-celled forms to multicellular forms 100 feet (30 meters) or more long, distinguished from plants by the absence of true roots, stems, and leaves and by a lack of nonreproductive cells in the reproductive structures: classified into the six phyla Euglenophyta, Crysophyta, Pyrrophyta, Chlorophyta, Phaeophyta, and Rhodophyta.

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algae British  

/ ˈældʒiː, ˈælɡəl /

plural noun

1. unicellular or multicellular organisms formerly classified as plants, occurring in fresh or salt water or moist ground, that have chlorophyll and other pigments but lack true stems, roots, and leaves. Algae, which are now regarded as protoctists, include the seaweeds, diatoms, and spirogyra

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algae Cultural  

1. Primitive organisms that contain chlorophyll but do not have structures, such as xylem and phloem, to transport fluids. Algae sometimes contain only a single cell, and nowadays they are not considered members of the plant kingdom.

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Discover More

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

• algal
  adjective

Etymology

Origin of algae

First recorded in 1790–1800; from New Latin, plural of Latin alga “seaweed”

Compare meaning

How does algae compare to similar and commonly confused words? Explore the most common comparisons:

• algae vs. seaweed

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.

Example Sentences

Because algae form the base of the ocean food web and produce roughly 70% of the oxygen in Earth's atmosphere, understanding these impacts is especially important.

From Science Daily • Jul. 3, 2026

Soon after completion of the work, the coating began to peel off and algae turned the pool's water a mucky green -- setbacks the president has blamed on vandals, without providing evidence.

From Barron's • Jul. 2, 2026

The $14.7-million repainting of the Reflecting Pool became particularly controversial last month after algae overtook the renovated pool and the new paint appeared to peel off.

From Los Angeles Times • Jul. 2, 2026

An academic has discovered "surprisingly rich" communities of microscopic algae in one of the most remote locations on Earth.

From BBC • Jun. 30, 2026

After a few seconds, they went back to doing what they had been doing before I appeared, which was either nibbling at the algae or staring into the ponds.

From "Life of Pi" by Yann Martel

Related Words

• seaweed