blue-green alga

noun

ˈblü-ˈgrēn- 

plural blue-green algae also blue-green algas

: cyanobacterium

Examples of blue-green alga in a Sentence

Recent Examples on the Web

Spirulina Spirulina is a blue-green alga, a plant-like organism that mainly lives in water. —Emmanuella Ogbonna, Health, 17 Sep. 2025

The algae partner can be either a green alga or a blue-green alga, known as cyanobacteria. —Howard Garrett, Dallas News, 17 June 2020

Word History

First Known Use

1880, in the meaning defined above

Kids Definition

blue-green alga

noun

ˌblü-ˌgrēn-

: any of a major group of microorganisms that typically live in water and undergo photosynthesis and that are now usually classified as bacteria or sometimes as plants

called also cyanobacterium

Medical Definition

blue-green alga

noun

ˈblü-ˈgrēn- 

: cyanobacterium