si > define
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.
- synonyms: silicon, atomic number 14
- 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))
- usage: "Today the United States is the only country in the world not totally committed to the Systeme International d'Unites"
- The syllable naming the seventh (subtonic) note of any musical scale in solmization.
by WordNet 3.0 © 2006 by Princeton University
A syllable applied, in solmization, to the note B; more recently, to the seventh tone of any major diatonic scale. It was added to Guido's scale by Le Maire about the end of the 17th century.
by Webster's Revised Unabridged Dictionary
(Military) SI stands for one of the following: special intelligence; United States Strategic Command strategic instruction
by Department of Defense Dictionary of Military and Associated Terms. 31 January 2011.