Sgt is an abbreviation for Sergeant. It is a military rank or a title given to a non-commissioned officer in the armed forces. The clue you provided suggests that "Sgt" might be referring to the abbreviation used in the title of the Beatles' album "Sgt. Pepper's Lonely Hearts Club Band," which was released in the 1960s.
Note: The provided meaning of the answer is for the latest New York Times crossword puzzle clue: Three-striper in the Army. Explanations are generated by AI and may be inaccurate.