offshoot offshoot {n.} A derivative; a side product. The discovery of nuclear reactors was ah offshoot of research in quantum physics. Categories: add yours {n.} Source: A Dictionary of American Idioms by A. Makkai, M.T. Boatner, J.E. Gates © 2024 To section: O Subscribe to: American IdiomsIdioms feedEnglish languageHome page and general feed Discuss