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definitions

si

[see]
noun Music.
  1. the syllable used for the seventh tone of a scale and sometimes for the tone B.

Origin of si

First recorded in 1720–30; see origin at gamut

Si

Symbol, Chemistry.
  1. silicon.

SI

  1. International System of Units.

S.I.

  1. Sandwich Islands.
  2. Staten Island.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for si

Contemporary Examples of si

Historical Examples of si

  • Si sed: "Yas; counted 'em on the wagon, counted 'em off agin, and counted 'em when I made 'em."

  • Si monumentum requiris, circumspice; it points us back to London.

    Howards End

    E. M. Forster

  • "Si———" began Csar, but the protest foundered in his dry throat.

    The Manxman

    Hall Caine

  • Si señor, a good padrone are you, and water it will be found for you.

    The Treasure Trail

    Marah Ellis Ryan

  • "You kin go, sir, and report to them people that it won't be did," answered Si firmly.

British Dictionary definitions for si

si

1
noun
  1. music a variant of te

si

2
the internet domain name for
  1. Slovenia

Si

1

Si Kiang

noun
  1. a variant transliteration of the Chinese name for the Xi

Si

2
the chemical symbol for
  1. silicon

SI

symbol for
  1. Système International (d'Unités)See SI unit
abbreviation for
  1. NZ South Island
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for si

"yes" in Italian, Spanish, Portuguese; from Latin sic "so" (see sic).

Online Etymology Dictionary, © 2010 Douglas Harper
si in Medicine

Si

  1. The symbol for the elementsilicon

SI

abbr.
  1. Système International (d'Unités) (International System of Units)
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.
si in Science

Si

  1. The symbol for silicon.

silicon

[sĭl′ĭ-kŏn′]
Si
  1. A metalloid element that occurs in both gray crystalline and brown noncrystalline forms. It is the second most abundant element in the Earth's crust and can be found only in silica and silicates. Silicon is used in glass, semiconductors, concrete, and ceramics. Atomic number 14; atomic weight 28.086; melting point 1,410°C; boiling point 2,355°C; specific gravity 2.33; valence 4. See Periodic Table.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.