A lender who loans you money to buy a home
A lender, usually a bank, is called a beneficiary in certain states. The beneficiary holds onto the deed of trust, which acts as a guarantee that you will repay your loan. If you fail to pay your loan (default), the beneficiary can give the trustee - the neutral third party who acts on behalf of the beneficiary - permission to foreclose on your property.
See:Deed of Trust
Mortgage definitions and Real Estate Terms, Consolidating loans, refinancing mortgages and reverse mortgage process available to anyone. This consumer information site contains several tools and guides to aid in purchasing or refinancing a home or commercial property.