1. [symbol] The ISO 3166-1 two-letter (alpha-2) code for Slovenia.
2. [symbol] The abbreviation for Système International d'Unités or the International System of Units, commonly known as the metric system.
3. [noun] (music) A syllable used in solfège to represent the seventh note of a major scale.
4. [symbol] (element symbol) Symbol for silicon.
5. [noun] A tetravalent nonmetallic element; next to oxygen it is the most abundant element in the earth's crust; occurs in clay and feldspar and granite and quartz and sand; used as a semiconductor in transistors.
6. [noun] 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); 'Today the United States is the only country in the world not totally committed to the Systeme International d'Unites'.
7. [noun] The syllable naming the seventh (subtonic) note of any musical scale in solmization.
