An irrevocable trust designed to save on estate tax. There are several kinds; with all of them, you keep income from trust property, or use of that property, for a period of years. When the trust ends, the property goes to the final beneficiaries you've named. These trusts are for people who have enough wealth to feel comfortable giving away a substantial hunk of property. They come in three flavors: grantor-retained annuity trusts (GRATs), grantor-retained unitrusts (GRUTs), and grantor-retained income trusts (GRITs).