State Marriage Defense Act of 2014 - Prohibits, for purposes of determining the meaning of any Act of Congress, or of any ruling, regulation, or interpretation of U.S. administrative bureaus and agencies, as applied with respect to individuals domiciled in a state or in any other territory or possession of the United States: (1) the term "marriage" from including any relationship that the state, territory, or possession does not recognize as a marriage; and (2) the term "spouse" from including an individual who is a party to a relationship that is not recognized as a marriage by that state, territory, or possession.