A guild ( GILD) is an association of artisans and merchants who oversee the practice of their craft/trade in a particular territory. The earliest types of guild formed as organizations of tradespeople belonging to a professional association. They sometimes depended on grants of letters patent from a monarch or other ruler to enforce the flow of trade to their self-employed members, and to retain ownership of tools and the supply of materials, but most were regulated by the local government. Guild members found guilty of cheating the public would be fined or banned from the guild.
https://en.wikipedia.org/wiki/Guild