Definition of Flag desecration
Flagrant misuse of flag by such acts as mutilation, defacement, or burning. Statutes making such acts criminal offenses (e.g., 18 U.S.C.A. § 700 (1989)) have been held to be unconstitutional as violating the freedom of expression protection of the First Amendment. See United States v. Eichman, 110 S.Ct. 2404 (1990). See also Desecrate.
That's the definition of Flag desecration in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.