palestra: a public place in ancient Greece or Rome devoted to the training of wrestlers and other athletes
playing field: a piece of land prepared for playing a game
systeme international d'unites: a complete metric system of units of measurement for scientists; fundamental quantities are length (meter) and mass (kilogram) and time (second) and electric current (ampere) and temperature (kelvin) and amount of matter (mole) and luminous intensity (candela)