algae

[al-jee]

plural noun

singular

alga 

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.

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

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

He says experts found that such a gas leak had the potential to destroy marine fauna and flora, reefs, algae and resources that allow fish to feed.

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In recent years large blooms of potentially toxic blue-green algae in Lough Neagh – caused in large part by long-term pollution – have grabbed the headlines.

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It follows the confirmation of high levels of blue-green algae.

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Harmful algae blooms had sickened marine life in each of the three years prior.

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Her duties include keeping them clean and free from fungi, bacteria and algae.

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Related Words

• seaweed