- 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
WordReference Random House Learner's Dictionary of American English © 2026
al•gae /ˈældʒi/USA pronunciation
n.pl.; sing.: -ga (-gə).
WordReference Random House Unabridged Dictionary of American English © 2026- Microbiologyany of many groups of one-celled organisms containing chlorophyll and usually living in watery or damp environments.
al•gae
(al′jē),USA pronunciation n.pl., sing. -ga (-gə).USA pronunciation
al′gal, adj.
- Microbiologyany of numerous groups of chlorophyll-containing, mainly aquatic eukaryotic organisms ranging from microscopic single-celled forms to multicellular forms 100 ft. (30 m) 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. Cf. blue-green algae.
- Neo-Latin, plural of Latin alga seaweed
Collins Concise English Dictionary © HarperCollins Publishers::
algae /ˈældʒiː; ˈælɡiː/ pl n ( sing alga /ˈælɡə/)
'algae' also found in these entries (note: many are not synonyms or translations):
algoid
- antheridium
- blue-green algae
- chlorophyll
- chloroplast
- conferva
- conjugation
- cryptogam
- cyanobacteria
- eyespot
- filament
- frog spit
- gametangium
- kingdom
- microflora
- pond scum
- protist
- protoctist
- red algae
- Red Sea
- scum
- seaweed
- stem
- thallus
- unicellular
- zoospore
- zygospore
- acinarious
- akinete
- algicide
- algology
- algophagous
- anabaena
- androspore
- antifouling
- aplanospore
- archaebacteria
- Archeozoic
- arthrospore
- azygospore
- bioherm
- bloom
- bryozoan
- Cambrian
- capsule
- carpogonium
- carpospore
- carpostome
- Ceylon moss
- charophyte