| Noun | 1. | Nostocaceae - blue-green algae bacteria family - a family of bacteria class Cyanobacteria, class Cyanophyceae, Cyanophyceae - photosynthetic bacteria found in fresh and salt water, having chlorophyll a and phycobilins; once thought to be algae: blue-green algae genus Nostoc - type genus of the family Nostocaceae: freshwater blue-green algae |