intestate and intestacy (def.)
The statutory rules that decide who inherits your estate if you die without a valid Will (intestate), or if your Will does not deal with everything you own.
The rules follow a fixed order of relatives and take no account of your wishes, your relationships, or who depends on you. Unmarried partners inherit nothing under them, however long you have lived together. Step-children inherit nothing unless they were legally adopted.
Making a valid Will is what allows you to decide for yourself instead.