algae

[ al-jee ]

plural noun

, singular al·ga [al, -g, uh].

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

/ 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

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 .

Notes

Algae supply a considerable part of the world's oxygen .

The most familiar algae are the greenish scum that collects in still water.

Derived Forms

• algal, adjective

Other Words From

• al·gal [al, -g, uh, l], adjective

Word History and Origins

Origin of algae¹

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

Word History and Origins

Origin of algae¹

C16: from Latin, plural of alga seaweed, of uncertain origin

Example Sentences

You may never have heard of this single-celled alga, but sailors and fishermen know its effect very well: the P. lunula algae are the organisms that occasionally make the see glow blue.

From Science Daily

A pungent, fishy rancid odor has been wafting through the coastal air in Los Angeles this week, an unfortunate consequence of beautiful bioluminescent algae that has graced local beaches for a fortnight.

From Los Angeles Times

Researchers are still working to better understand how these algae blooms affect ocean life and humans.

From Los Angeles Times

His careful movements through the delicate layer of silt and algae at the lake’s bottom ensured a clear view.

From BBC

Corals exist in a symbiotic partnership with a special type of marine plant - a species of algae - which lives inside the coral, providing it with food and giving it its bright colour.

From BBC

Related Words

• seaweed