Trustor

An individual or organization that gifts funds or assets to others by transferring fiduciary duty to a third party trustee that will maintain the assets for the benefit of the beneficiaries.

Investopedia Says:
Also referred to as a grantor, the trustor is the party that generally donates or gifts assets to others.

Person who establishes a Trust for the benefit of another, and turns property over to a Trustee for distribution to the Beneficiary. Also known as a donor or settlor.

One who creates a Trust. Also, one who gives a Deed of Trust as Collateral for a loan.
Example: William became a trustor. He turned money over to a bank's trust department, which invested the funds in income-producing Real Estate for the benefit of William's children.

One who creates a trust; more often called the settlor.