DF meaning in Military and Defence ?

The 1st Special Forces Operational Detachment–Delta (1st SFOD-D), commonly referred to as Delta Force, Combat Applications Group (CAG), "The Unit", or within JSOC as Task Force Green, is a special operations force of the United States Army, under operational control of the Joint Special Operations Command. The unit is tasked with missions primarily involving counter-terrorism, hostage rescue, direct action, and special reconnaissance, often against high-value targets. Delta Force and its Navy and Air Force counterparts, DEVGRU and the 24th Special Tactics Squadron, are the U.S. military's tier one special mission units tasked with performing the most complex, classified, and dangerous missions directed by the National Command Authority.

Most Delta Force operators are selected from the United States Army Special Operations Command's elite Special Forces Groups and the 75th Ranger Regiment, as well as from other special operations and conventional forces from the army and sometimes different military branches.