1. A gelatinous, colonial cyanobacterium (blue-green alga) that forms jelly-like masses in freshwater and damp soil.
Usage: biology; microbiology

Examples

• Nostoc is commonly found in ponds and wet soil after heavy rain.
• The gelatinous colonies of nostoc can expand and contract depending on moisture levels.
• Biologists study nostoc because it can fix nitrogen from the atmosphere.
• Nostoc has been used in traditional Asian cuisine for centuries.
• Under the microscope, nostoc reveals chains of cells arranged in a distinctive pattern.