A group of diverse species that share common characteristics or habits.
A group or association mainly of tradespeople made up of merchants, craftspeople, or artisans for mutual aid, particularly in the Middle Ages.
An organized group of players who regularly play together in a multiplayer game.
A corporation.
Any of many symbiotic organisms, being associations of algae and fungi, often found as white or yellow-to-blue–green patches on rocks, old walls, etc.
Something which gradually spreads across something else, causing damage.