Dictionary.com
Thesaurus.com

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.

El cambio se reflejó en el campo en la NLDS, donde Sasaki atacó a los Phillies con un estilo que transmitía una actitud de «golpéeme si puede».

From Los Angeles Times • Oct. 10, 2025

Jesus showed himself to the disciples, In quel tempo, quando si fu manifesta -

From BBC • Apr. 25, 2025

Para muchos investigadores, la gran pregunta es si, de ser electa, Sheinbaum Pardo continuará, revisará, o incluso revertirá las impopulares políticas relacionadas con la ciencia de su mentor.

From Science Magazine • May 8, 2024

“Vacúnate como regalo de Año Nuevo si aún no lo has hecho”, dijo Schaffner.

From New York Times • Dec. 31, 2023

"Pregúntale si quiere algo para tomar," Papá said, bowing his head and smiling.

From "Breaking Through" by Francisco Jiménez