1. A group of photosynthetic bacteria that contain chlorophyll and produce oxygen as a byproduct of photosynthesis; also called blue-green algae.
Usage: Plural noun; singular form is cyanobacterium; Scientific/technical term; Often used in biology and environmental science contexts

Examples

• Cyanobacteria are among the oldest known organisms on Earth, dating back billions of years.
• The lake's water turned green due to a bloom of cyanobacteria.
• Cyanobacteria play a crucial role in the nitrogen cycle by fixing atmospheric nitrogen.
• Some cyanobacteria produce toxins that can harm fish and other aquatic life.
• Scientists study cyanobacteria to understand the origins of photosynthesis.
• Excess nutrients in the water can cause rapid growth of cyanobacteria.