Historically, a Guild was associated with crafts. From
Wikipedia A guild is an association of partisans who control the practice of their craft in a particular town. The earliest types of guild were formed as confraternities of workers. They were organized in a manner something between a trade union, a cartel, and a secret society. They often depended on grants of letters patent by a monarch or other authority to enforce the flow of trade to their self-employed members, and to retain ownership of tools and the supply of materials. A lasting legacy of traditional guilds are the guildhalls constructed and used as meeting places.
One of the legacies of the guilds, the elevated
Windsor Guildhall was originally a meeting place for guilds, as well as magistrates' seat and
town hall.
An important result of the guild framework was the emergence of universities at Bologna, Paris, and Oxford around the year 1200; they originated as guilds of students as at Bologna, or of masters as at Paris.[1]
More recently, from
Wikipedia:
A guild (or ecological guild) is any group of species that exploit the same resources, often in related ways.[1][2][3] As can be seen from the list of examples below, it does not follow that the species within a guild occupy the same, or even similar, ecological niches. Guilds are defined according to the locations, the attributes, and the activities of their component species; for example, their mode of acquiring nutrients, their mobility, and the zones of their habitat that they occupy or otherwise exploit. The number of guilds occupying an ecosystem is termed its disparity. Members of a guild within a given ecology could be competing for some resources (such as space or light), while cooperating in resisting wind stresses, attracting pollinators, or detecting predators, such as happens among savannah-dwelling antelope and zebra.
And, from another
Wikipedia about Clans:
In computer and video gaming, a clan or guild is an organised group of players that regularly play together in particular (or various) multiplayer games. Some people might say, that a "clan" or "guild" becomes like a family, and that all opinions and decisions represent each single member in the "clan" or "guild".[1] These games range from groups of a few friends to 1000-person organizations, with a broad range of structures, goals and members. The lifespan of a clan also varies considerably, from a few weeks or months to over a decade. Numerous clans exist for nearly every online game available today, notably in first-person shooters, massively multiplayer games, role-playing video games, and strategy games.