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.

---

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

---

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.

---

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

Along the easternmost point of the coast, sea women stuff "stone flowers" -- as the algae is called in Taiwanese and Mandarin -- into net sacks.

From Barron's • Jun. 30, 2026

He has to repair the Lincoln Memorial Reflecting Pool after it was covered in algae following a resurfacing job.

From The Wall Street Journal • Jun. 28, 2026

But the algae has been detected in a number of places around the Lough and elsewhere.

From BBC • Jun. 27, 2026

The answer, for that sample, was: mostly Desmodesmus, a green algae that gobbles up phosphorus and nitrogen.

From Slate • Jun. 27, 2026

In structure and pigment content they are the images of prokaryotic blue-green algae.

From "The Lives of a Cell" by Lewis Thomas

Related Words

• seaweed