Domicile
Your permanent legal home — the state where you intend to live indefinitely. Your domicile determines which state's laws govern your estate, where your will is probated, and which state can tax your estate.
Legal Definition
A person's fixed, permanent, and principal residence to which they intend to return and remain indefinitely, which determines the applicable law for intestacy, will validity, and estate taxation.
Practical Example
Joan splits her time between homes in New York and Florida. She registers to vote in Florida, gets a Florida driver's license, and files a declaration of domicile there. Florida (which has no state estate tax) is now her domicile for estate planning purposes.