alga

American

[al-guh] / ˈæl gə /

noun

any organism belonging to one of the numerous groups of algae.

alga Scientific

/ ăl′gə /

Any of various green, red, or brown organisms that grow mostly in water, ranging in size from single cells to large spreading seaweeds. Like plants, algae manufacture their own food through photosynthesis and release large amounts of oxygen into the atmosphere. They also fix large amounts of carbon, which would otherwise exist in the atmosphere as carbon dioxide. Algae form a major component of marine plankton and are often visible as pond scum and blooms in tidal pools. Land species mostly live in moist soil and on tree trunks or rocks. Some species live in extreme environments, such as deserts, hot springs, and glaciers. Although they were once classified as plants, the algae are now considered to be protists, with the exception of the cyanobacteria, formerly called blue-green algae. The algae do not form a distinct phylogenetic group, but the word alga serves as a convenient catch-all term for various photosynthetic protist phyla, including the green algae, brown algae, and red algae.

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alga algae

"More than 80 fish were observed around a single floating alga," said Mr Mazoudier.

From Science Daily ● Jan. 31, 2024

Blue-green algae is not actually an alga but rather a type of bacteria called cyanobacteria.

From BBC ● Jul. 10, 2023

This is the first recorded example of an alga practicing an aquatic equivalent to pollination.

From Scientific American ● Jul. 28, 2022

The alga could be providing a place for younger isopods to hide from predators, as Idotea is often the same color as the plant.

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

But the gas that’s released in larger quantities is methane, which forms underwater as plants and algae break down and then bubbles to the surface.

From Los Angeles Times ● Aug. 27, 2026

The largest changes were measured in the marginal ice zone, a narrow region where melting sea ice meets open water and marine algae are especially productive.

From Science Daily ● Aug. 18, 2026

Within weeks of the renovation’s completion, numerous defects were spotted, with a liner installed on the bottom of the pool peeling in various places, and algae again infesting the water.

From Slate ● Aug. 13, 2026

Liz Cheslett-Davey, catchment co-ordinator at the EA, said the algae could "appear quickly and the conditions that encourage it to form aren't always easy to predict".

From BBC ● Aug. 12, 2026

He climbed to the place over the slippery rocks, held himself firmly, and gently reached down and parted the brown algae.

From "Cannery Row" by John Steinbeck

Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023