Per Stirpes

Per stirpes is a law Latin phrase (meaning by branch) used in wills that specifies that each family branch of a group of beneficiaries is to receive an equal share of an estate, usually to take effect in the case where the first choice beneficiary has died and their share is to be redistributed to their descendants.
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Lat. Term used to designate a system of inheritance under which children take among them the share which their parent would have taken had he survived the decedent. Thus the children are said to claim their shares by representing their parent.