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si

1 American  
[see] / si /

noun

Music.
  1. the syllable used for the seventh tone of a scale and sometimes for the tone B.


Si 2 American  
Symbol, Chemistry.
  1. silicon.


SI 3 American  
S.I. 4 American  

abbreviation

  1. Sandwich Islands.

  2. Staten Island.


SI 1 British  

symbol

  1. Système International (d'Unités) See SI unit

"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

abbreviation

  1. 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
Si 2 British  
/ ʃiː /

noun

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

"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

Si 3 British  

symbol

  1. silicon

"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

si 4 British  
/ siː /

noun

  1. music a variant of te

"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

si 5 British  

abbreviation

  1. Slovenia

"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

Etymology

Origin of si

First recorded in 1720–30; see origin at gamut

Vocabulary lists containing si

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

See Examples For:

That response went viral and now the phrase “¿Y si sí?” is chanted by Mexicans as they cheer on their national soccer team — a squad that boasts four wins without conceding a goal.

From Los Angeles Times Jul. 5, 2026

It opens with a big-band cover of the 1920 standard “Whispering,” leading into the track, and closes with a reference to the 1947 French cabaret song “C’est si Bon.”

From The Wall Street Journal Jun. 15, 2026

In the city, the Queen was affectionately called si tau por, which means "boss lady" in Cantonese.

From BBC Sep. 14, 2022

In Spanish, Eso, si que es basically translates as "That's what it is!"

From Salon Nov. 8, 2021

This is another way to read it, although I am told a normal brain will not grasp it: Ti morf sgniht wen nrael nac uoy dna tnorf ot kcab koob tnereffid a si ti.

From "The Poisonwood Bible" by Barbara Kingsolver

I saved up and bought a red 1989 Honda CRX Si.

From Los Angeles Times Jun. 22, 2026

To test the theory, Fang and Si conducted laboratory experiments using a thin layer of water driven by electromagnetic forces.

From Science Daily Jun. 3, 2026

Together with his brother Samuel Irving Newhouse Jr., known as Si, Donald oversaw and expanded the sprawling media company that was founded by their father more than a century ago.

From The Wall Street Journal May 27, 2026

The "Laudato Si" encyclical, which denounced mankind's ruthless exploitation of the environment, was hailed by experts for its scientific grounding.

From Barron's May 23, 2026

Princess Si Ling-chi was sitting under a mulberry tree when a silkworm cocoon fell into her teacup.

From "Middlesex: A Novel" by Jeffrey Eugenides

The painting, which came from the private collection of media magnate SI Newhouse, is also now the fourth most expensive artwork ever sold at auction, according to ARTnews.

From BBC May 19, 2026

The memorial itself holds a "tiered system of commemoration", says Korean research company SI Analytics.

From BBC May 7, 2026

About 140 graves sit on the west side of the graveyard and 138 that sit on the opposite site, according to a satellite image taken in early April provided by SI Analytics.

From BBC May 7, 2026

She said she was surprised to see high recognition of Sports Illustrated with the Gen Z crowd, and credits SI for Kids, the spin-off publication for younger readers launched in 1989.

From Los Angeles Times Apr. 5, 2026

Oct-ober SI “Did you give Tony my thank-you note?”

From "The Dead and the Gone" by Susan Beth Pfeffer

“The joy of his life was his connection to the S.I. Newhouse School of Public Communications at Syracuse,” his son, Steven, said Tuesday.

From The Wall Street Journal May 27, 2026

According to a new survey titled “The American Journalist Under Attack,” released by Syracuse University’s S.I.

From Washington Times Dec. 30, 2023

Nearly half a century ago, Californians elected Republican S.I.

From Los Angeles Times Jul. 9, 2023

But he also edited The New Yorker for five years before departing over “conceptual differences” with publisher S.I.

From Seattle Times Jun. 14, 2023

"Thomas Grogan, Rockville, S.I., thirty-eight cents for coal, etc."

From Tom Grogan by Smith, Francis Hopkinson

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