Activities that are permitted when they otherwise would not be permitted because of a
grandfather clause. A grandfather clause is a portion of a new law,
regulation, or anything else that exempts certain persons or businesses from abiding by it. For example, suppose a country passes a law stating that it is illegal to own a cat. A grandfather clause may allow persons who already own cats to continue to keep them, but would prevent people who do not own cats from buying them. In this case, owning a cat is a grandfathered activity. Grandfathered activities are controversial, but they are also relatively common.