Focus on the pronunciation of SI
English definition of “SI”
/ˌesˈaɪ/ noun MEASURES
› abbreviation for Système International: a system of units of measurement used internationally. SI units include the metre, kilogram, second, ampere (= unit of electric current), candela (= unit of light), kelvin (= unit of temperature), and the mole (= unit of the amount of a substance): The chart shows you how to convert from a conventional unit to an SI unit.