Definition of Espionage

Espionage, or spying, has reference to the crime of “gathering, transmitting or losing” information respecting the national defense with intent or reason to believe that the information is to be used to the injury of the United States, or to the advantage of any foreign nation. 18 U.S.C.A. § 793; Rosenberg v. United States, 346 U.S. 273, 73 S.Ct. 1152, 97 L.Ed. 1609. See Internal security acts.

That's the definition of Espionage in Black's Law Dictionary 6th Edition. Courtesy of