enlarge on enlarge on or enlarge upon or expand on or expand upon {v.} To talk or write more about; say or explain more completely or at greater length. The teacher enlarged on the uses of atomic power. Categories: add yours {v.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 To section: E Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Discuss