You may hear the terms "heir" and "legatee" used interchangeably, but the words have two different legal meanings. An heir inherits the estate of a person who died by relationship, descent, will or legal process wheras a legatee is any entity or person who received an inheritance from a will.
A person's blood relatives are usually his heirs, as well as his surviving spouse and adopted children. Heirs include children, parents, siblings, nieces and nephews, parents, grandparents, aunts, uncles and cousins. If someone dies without leaving a will, state intestacy laws decide the inheritance order and the size of the shares. Although intestacy laws differ by state, spouses and children usually inherit first. For example, in South Carolina, a surviving spouse and child split a deceased person's estate equally. If the deceased didn't have children or a surviving spouse, his living parents inherit next.
A legatee may not be related to the person leaving her an item under his will. For example, Bob's will leaves a car to his friend, Carol. Carol isn't his heir, as she's not married to Bob or related to him by blood or adoption, but she is his legatee because she received an item from him in his will. A legatee may be a business, charitable organization or other agency; some states refer to a legatee as a "devisee."
The blood relatives of a person's predeceased spouse or his stepchildren may be the heirs to his estate if he dies without leaving a will, depending on state law. This occurs if he doesn't have any other relatives to inherit from him. For example, in California, the parents of a predeceased spouse inherit from the estate of a deceased son-in-law if he has no surviving relatives or stepchildren. The state may take a person's estate if he doesn't have any heirs under the state's intestacy laws. For example, the state takes the estate of a person who died intestate with no surviving family or stepchildren in South Carolina.
If a deceased person created a trust in his will, the trust beneficiaries aren't legatees even though they're inheriting through the trust. The legatee is the trust itself. The deceased person's heirs -- such as his children -- may be then be beneficiaries of the trust.