drill instructor

Noun



 * 1)  The generic term for the principal instructor of fresh military recruits undergoing basic training in the various branches of the United States military, routinely abbreviated to the initialism DI; always filled by enlisted personnel (a sergeant or petty officer).
 * Army: drill sergeant
 * Navy: recruit division commander
 * Marine Corps: drill instructor
 * Air Force: military training instructor
 * Coast Guard: company commander