Governance through trade union organizations is known as Syndicalism. Syndicalism is a political and economic theory that advocates for the transfer of industrial production and distribution to worker-controlled organizations, such as trade unions. It promotes the idea that workers should take ownership and control of the means of production, rather than being subject to capitalist employers.

Guild Socialism, on the other hand, is a theory that supports the organization of workers into decentralized, self-governing guilds that would collectively own and control the means of production. Fabian Socialism is a more gradualist approach to socialism, emphasizing the use of democratic processes and government intervention to bring about a fairer society. Liberalism, meanwhile, is a political philosophy that emphasizes individual rights, free markets, and limited government intervention.

Therefore, Syndicalism is the correct term to describe governance through trade union organizations.