A grandfather clause is an exception given to existing businesses or individuals when new regulations are enacted. Grandfather clauses are often granted in zoning regulations. For example, if a business is operating in an area that has commercial zoning, and the zoning is changed to residential, the business may be allowed to continue operating. If the business is sold, though, the property would have to comply with the new zoning restrictions.
Grandfather Clauses in U.S. History
You may have heard the term "grandfather clause" used in a historical context. During the Reconstruction Era, grandfather clauses were used to keep African-Americans from being allowed to vote.