"Fiduciary" is the generic term applied to anyone acting on behalf of another to manage assets that have been entrusted to the Fiduciary. Most Wills appoint two types of fiduciaries: An "Executor" and a "Trustee." The Executor is the person generally responsible for handling the "post-death process," which involves collecting and preserving your assets, filing all required tax returns (for you and for your estate), winding up your affairs, and fulfilling the provisions of your Will (i.e., establishing and funding the trusts created in your Will, re-titling and distributing assets to the proper recipients, etc.). The Trustee is the person responsible for the (usually) long term job of administering the trusts you create (i.e., managing investments, making distributions to the beneficiaries of the trust, filing tax returns for the trust, etc.). The same person can be both a Fiduciary and a beneficiary, and the same person can be both an Executor and a Trustee. Different trusts can have different Trustees.