guild

Short definition from Wiktionary

Noun

1. 1
   A group or association mainly of tradespeople made up of merchants, craftspeople, or artisans, particularly in the Middle Ages, established to oversee and protect their specific commercial interests and to provide mutual aid.
2. 2
   A corporation.
3. 3
   A group of diverse species that share common characteristics or habits.
4. 4
   An organized group of players who regularly play together in a multiplayer game.

Proper noun

1. 1
   A surname.