A more thorough explanation:

Cotrustee (also known as joint trustee) refers to a person who manages a trust along with other trustees. A trust can have multiple trustees, which may be necessary for large trusts or those involving complex assets. The trustees can have equal authority or specific roles to play, but they are all bound by the traditional fiduciary duties to the beneficiaries as in every trust.

For example, a wealthy individual may establish a trust to manage their assets and provide for their family after their death. They may appoint two of their children as cotrustees to manage the trust together. Both cotrustees have equal authority and must work together to make decisions that benefit the trust's beneficiaries.

In another example, a business owner may establish a trust to manage their company's assets and ensure their employees are taken care of after their death. They may appoint a cotrustee who is an experienced accountant to manage the financial aspects of the trust while another cotrustee, who is a family member, manages the day-to-day operations of the business.

These examples illustrate how cotrustees can work together to manage a trust and ensure that the beneficiaries' interests are protected. By appointing multiple trustees, the trust can benefit from their different skills and expertise.