Legal Definition of Co-Trustee: One of two or more people who jointly hold, manage and distribute property for the benefit of another under a trust; joint trustee | Discover the legal definition and responsibilities of a Co-Trustee in managing and distributing property under a trust. Learn the importance of understanding this role for business owners and gain insights from practical examples. Make informed decisions when establishing or participating in a trust by comprehending the duties and obligations of a Co-Trustee