Marital Deduction Law and Legal Definition
A marital deduction is an estate tax deduction that allows one spouse to transfer upon death an unlimited amount of property to his/her spouse without creating liability for estate or gift tax. The disadvantage is that, although you can transfer any amount that you want to your spouse, if your spouse survives you (and does not remarry), there will be no marital deduction available to lessen the estate tax liability at his or her later death.
The marital deduction may only be taken for transfers of property between spouses. Whether a couple is married or not is determined under state law. Some states recognize "common law" marriages where cohabitation has lasted a certain number of years, but other states do not recognize such relationships. For transfers at death, the marital deduction applies only to property included in the gross estate for federal estate tax purposes.