1. English physicist who discovered the pion (the first known meson) which is a subatomic particle involved in holding the nucleus together (1903-1969) • Syn: Cecil Frank Powell • Instance Hypernyms: physicist 2. United States general who was the first African American to serve as chief of staff; later served as Secretary of State under President George W. Bush (born 1937) • Syn: Colin Powell, Colin luther Powell • Instance Hypernyms: general, full general, statesman, solon, national leader