Dictionary.com
definitions
  • synonyms

si

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

Origin of si

First recorded in 1720–30; see origin at gamut

Si

Symbol, Chemistry.
  1. silicon.
Show More

SI

S.I.

  1. Sandwich Islands.
  2. Staten Island.
Show More
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

  • He had hardly been in speaking distance of such women as Si's mother and sisters.


British Dictionary definitions for si

si

1
noun
  1. music a variant of te
Show More

si

2
the internet domain name for
  1. Slovenia
Show More

Si

1

Si Kiang

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

Si

2
the chemical symbol for
  1. silicon
Show More

SI

symbol for
  1. Système International (d'Unités)See SI unit
Show More
abbreviation for
  1. NZ South Island
Show More
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).

Show More
Online Etymology Dictionary, © 2010 Douglas Harper

si in Medicine

Si

  1. The symbol for the elementsilicon
Show More

SI

abbr.
  1. Système International (d'Unités) (International System of Units)
Show More
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.
Show More

silicon

[sĭlĭ-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.
Show More
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.