from Wiktionary, Creative Commons Attribution/Share-Alike License
- proper n. A taxonomic phylum within the kingdom Bacteria — (formerly within subkingdom Eubacteria) - the blue-green algae.
- proper n. A taxonomic class within the phylum Cyanobacteria.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. predominantly photosynthetic prokaryotic organisms containing a blue pigment in addition to chlorophyll; occur singly or in colonies in diverse habitats; important as phytoplankton
Latin cyano a blue gemstone + bacteria (Wiktionary)