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si

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noun Music.
the syllable used for the seventh tone of a scale and sometimes for the tone B.
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“Was” is used for the indicative past tense of “to be,” and “were” is only used for the subjunctive past tense.

Origin of si

First recorded in 1720–30; see origin at gamut

Other definitions for si (2 of 4)

Si

Symbol, Chemistry.
silicon.

Other definitions for si (3 of 4)

Other definitions for si (4 of 4)

S.I.

abbreviation
Sandwich Islands.
Staten Island.
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2022

How to use si in a sentence

British Dictionary definitions for si (1 of 5)

si1
/ (siː) /

noun
music a variant of te

British Dictionary definitions for si (2 of 5)

si2

the internet domain name for
Slovenia

British Dictionary definitions for si (3 of 5)

Si1

Si Kiang

/ (ʃiː) /

noun
a variant transliteration of the Chinese name for the Xi

British Dictionary definitions for si (4 of 5)

Si2

the chemical symbol for
silicon

British Dictionary definitions for si (5 of 5)

SI

symbol for
Système International (d'Unités)See SI unit
abbreviation for
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

Medical definitions for si (1 of 2)

Si

The symbol for the elementsilicon

Medical definitions for si (2 of 2)

SI

abbr.
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.

Scientific definitions for si

Si

The symbol for silicon.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
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