"The Reserve Officers' Training Corps (ROTC) is a college-based program for training commissioned officers of the United States armed forces. ROTC officers serve in all branches of the U.S. armed forces. ROTC graduates constitute 56 percent of U.S. Army officers, 11 percent of U.S. Marine Corps officers, 20 percent of U.S. Navy officers, and 41 percent of U.S. Air Force officers, for a combined 39 percent of all active duty officers in the Department of DefenseUnder ROTC, a student may receive a competitive, merit-based scholarship, covering all or part of college tuition, in return for an obligation of active military service after graduation. The U.S. Coast Guard offers a similar program to ROTC under a different name: CSPI .The student attends college like other students, but also receives basic military training and officer training for his chosen branch of service, through the ROTC unit at the college or university. The student participates in regular drills during the school year, and extended training activities during the summer. Army ROTC units are organized as brigades, battalions, and companies. Air Force ROTC units are detachments with the students organized into wings, groups, squadrons, and flights. Army and Air Force ROTC students are referred to as cadets. Navy ROTC units are organized as battalions, and also include Marine ROTC students. Marine ROTC students may be formed in a separate company when the program includes sufficient numbers. Navy ROTC students are referred to as midshipmen. The term of obligatory service varies among the services. Army ROTC students who receive an Army ROTC scholarship or enter the Army ROTC Advanced Course must agree to complete an eight-year period of service. This can include three years active duty (four years for scholarship winners), with the balance in the Individual Ready Reserve (IRR). The service obligation for a Navy ROTC student is five years in the Navy, or four years in the Marine Corps. The service obligation for an Air Force ROTC student is four years, or six years for Combat Systems Officers or Air Battle Management officers, or ten years for pilots". Source: Wikipedia