red algae

American  

plural noun

Biology.

red alga singular

1. marine algae of the phylum Rhodophyta, in which the chlorophyll is masked by a red or purplish pigment.

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red algae British  

plural noun

1. Also called: red seaweed.  the numerous algae that constitute the phylum Rhodophyta , which contain a red pigment in addition to chlorophyll. The group includes carrageen, dulse, and laver

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Other Word Forms

• red-algal
  adjective

Etymology

Origin of red algae

First recorded in 1850–55

Example Sentences

See Examples For:

red algae

Dusky farmerfish in East Asia grow “crops” of red algae by assiduously “weeding out less palatable foods” and have effectively domesticated a type of shrimp whose waste fertilizes the algae and boosts yields.

From The Wall Street Journal ● Jun. 19, 2026

Galdieria extract blue comes from a unicellular red algae, which is an organism that thrives in extreme marine and terrestrial environments, according to the National Institutes of Health.

From Los Angeles Times ● May 14, 2025

Kombu hails from kelp and is thicker and more substantial, while nori is derived from red algae.

From Salon ● May 14, 2024

They think these reproduce by infecting the red algae.

From Science Magazine ● Apr. 8, 2024

They gobbled red algae until their bodies turned the color of blood.

From "The House of the Scorpion" by Nancy Farmer