si

¹ American  

[see] / si /

noun

Music.

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

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Si ² American  

Symbol, Chemistry.

1. silicon.

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SI ³ American  

abbreviation

1. International System of Units.

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S.I. ⁴ American  

abbreviation

1. Sandwich Islands.

2. Staten Island.

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SI ¹ British  

symbol

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

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abbreviation

1. South Island

Si ² British  

/ ʃiː /

noun

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

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Si ³ British  

symbol

1. silicon

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si ⁴ British  

/ siː /

noun

1. music a variant of te

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si ⁵ British  

abbreviation

1. Slovenia

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Etymology

Origin of si

First recorded in 1720–30; see origin at gamut

Example Sentences

Cuando le preguntaron si los aficionados del Citizens Bank Park se burlaban de él, respondió que no entendía lo que decían.

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

This time the boys grinned, muttering, “That’s right, Bernie,” or “Que si, sheriff,” things like that.

From "The Milagro Beanfield War" by John Nichols