Si definitions

WordNet (r) 3.0 (2005)

n
1: 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 [syn: silicon, Si, atomic number 14]
2: 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" [syn: Systeme International d'Unites, Systeme International, SI system, SI, SI unit, International System of Units, International System]
3: the syllable naming the seventh (subtonic) note of any musical scale in solmization [syn: ti, te, si]

Merriam Webster's

noun Etymology: Italian Date: 1728 ti II

Merriam Webster's

abbreviation Etymology: French Système International d'Unités International System of Units

Merriam Webster's

I. symbol silicon II. geographical name — see xi

Oxford Reference Dictionary

abbr. 1 (Order of the) Star of India. 2 the international system of units of measurement (F Système International).

Oxford Reference Dictionary

symb. Chem. the element silicon.

Oxford Reference Dictionary

n. Mus. = TE. Etymology: F f. It., perh. f. the initials of Sancte Iohannes: see GAMUT

Webster's 1913 Dictionary

Si Si [It.] (Mus.) 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.