Yes, guilds arent like guilds in other MMOS (that would be closer to a family in CoE, and maybe your local community such as settlement or county).
A guild is like an organization, usually specialized in some craft, like smithing, cartography, woodworking, etc.
You can join multiple guilds as long as they’re not of the same type.
In fact you can technically even join guilds of the same type (not “legally” though) because your character has identities, so you can have a fake identity on your character (wearing a disguise) and join another guild, because the other guild will see your fake identity as a different person. This is risky though, there will be consequences if they find out.