Answer:
The provision when an old rule continues to be applied to some existing institutions while new rules are applied to future cases is known as grandfather clause. The ones exempted from the new rules are said to be having grandfather rights. The exemption may be for a limited time. The grandfather provisions are used in compromises especially when the government doesn't want to upset an established political institution.
This term had its origins in nineteenth-century amendments which were passed by many southern states in which there were new requirements for literacy tests and property restrictions to get registered for the vote. The states exempted those who had voting rights from the time before the civil war from these provisions, African Americans slaves were the most affected by these rules. These clauses were ruled unconstitutional but the term continued to be in use. The first grandfather laws were passes in 1898.
