The American Heritage® Dictionary of the English Language, 4th Edition
n. A freshwater blue-green alga of the genus Nostoc, forming spherical colonies of filaments embedded in a gelatinous substance.
The Century Dictionary and Cyclopedia
n. A plant of the genus Nostoc.
n. A genus of fresh-water algæ belonging to the Cryptophyceæ or Cyanophyceæ, the lowest group of algæ, and typical of the family Nostocaceæ and subclass Nostochineæ.
WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
n. found in moist places as rounded jellylike colonies
Word Usage
"Dr. Edwards writes of the substance that had so completely, or beautifully -- if beauty is completeness -- been identified as nostoc -- "It turned out to be lung-tissue also.""