Drill instructors are trainers in the military who train recruits the fundamentals of discipline, proper procedures and teamwork. Other terms that can be used to refer to drill instructors include drill sergeants, instructors, training sergeants, crew leaders, platoon sergeants or squad leaders. These positions are held by experienced enlisted personnel who have undergone highly rigorous training programs to learn the skills of an effective drill instructor. The role of drill instructors is critical in military training, as they are responsible for shaping the mindset and abilities of new recruits to prepare them for the challenges of military service. Using varied synonyms helps to acknowledge the vital role played by these persons in the military and highlights the importance of their work.