The Full Form of ROTC is Reserve Officers’ Training Corps.

The Reserve Officers’ Training Corps (ROTC) is a group of college and university-based officer training programs for training commissioned officers of the United States Armed Forces

While ROTC graduate officers serve in all branches of the U.S. military, the U.S. Marine Corps and the U.S. Coast Guard do not have their own respective ROTC programs, but graduates of Naval ROTC programs have the option to serve as officers in the Marine Corps contingent on meeting Marine Corps requirements. The Coast Guard has no ROTC program and its officers can only be commissioned via the U.S. Coast Guard Academy, Coast Guard Officer Candidate School, interservice transfer from another U.S. military service following completion of at least 4 years commissioned service in that other branch of the U.S. military (e.g. such as interservice transfers for officers designated as Army Aviators, USN and USMC Naval Aviators and USAF Pilots), or via the Coast Guard College Student Pre-Commissioning Initiative (CSPI), although the CSPI program is only available at colleges and universities designated as a Minority Serving Institute (MSI) or with a student population of at least 50% minorities for the past three years.