Meanings
si1
- entertainmentA syllable used in solfège to represent the seventh note of a major scale.
SI2
- International System of Units
1 more example
The reason for the change to the International System of Measurement (SI) units was that over time the prototype lost atoms and therefore mass because it is “susceptible to damage and environmental factors,” according to the National Physical Laboratory (NPL), which houses Kilo 18, Britain’s copy of Le Grand K.
2018 November 13, Matthew Robinson and Lianne Kolirin, “The world has just redefined the kilogram”, in CNN
SI3
- abbreviationinitialismInitialism of Smithsonian Institution.
- abbreviationinitialismInitialism of Sports Illustrated.
1 more example
“We have said from the start that our top priorities are to keep Sports Illustrated alive, uphold the legacy of the institution and protect our union jobs. We look forward to discussing a future with Minute Media that does that,” Emma Baccellieri, staff writer for SI and vice chair for the SI Union, said in a statement.
2024 March 18, Oliver Darcy and Liam Reilly, “Sports Illustrated to avert shutdown as it gets a fresh start under new publisher”, in CNN Business
- abbreviationcountableinitialismuncountableengineeringInitialism of systems integration.
- abbreviationcountableinitialismuncountableInitialism of self-injury.
- abbreviationcountableinitialismuncountableInitialism of suicidal ideation.
- abbreviationcountableinitialismslanguncountablelifestyleInitialism of self-insertion (of the author into fan fiction).
- abbreviationcountableinitialismuncountableengineeringInitialism of spark ignition.
- abbreviationcountableinitialismuncountableInitialism of supporting information.
- abbreviationcountableinitialismuncountableInitialism of special intelligence.
- abbreviationcountableinitialismuncountablebusinessInitialism of systematic internaliser.
- abbreviationcountableinitialismuncountableInitialism of swarm intelligence.
- abbreviationcountableinitialismuncountableInitialism of synthetic intelligence.
- AustraliaCanadaUKabbreviationcountableinitialismuncountablelawInitialism of statutory instrument.
1 more example
The scope of SIs varies greatly, from the technical (e.g. to set or vary the dates on which different provisions of an Act will come into force, to change the levels of fines or penalties for offences or to make consequential and transitional provisions) to the much wider-ranging, such as filling out the broad provisions in Acts.
2016 December 15, Richard Kelly, Statutory Instruments, House of Commons Library Briefing Paper 6509, archived from the original on 07 Jan 2022, page 1 - abbreviationcountableinitialismuncountableInitialism of subinspector (of police, etc).
India's first transgender SI
- abbreviationcountableinitialismuncountabledivingInitialism of surface interval.
Si4
alternative Sy
- A diminutive of the male given name Simon.
- A diminutive of the female given name Simone.
- A diminutive of the male given name Silas.
Si5
alternative Su · alternative Ssu · alternative Szu
- A county of Suzhou, Anhui, China.
Si county in Anhui province locked down its 760,000 residents and suspended public traffic as it reported 288 cases on Saturday.
2022 July 4, Sophie Yu, Stella Qiu, Ryan Woo, “Eastern China cities tighten COVID curbs as new clusters emerge”, in William Mallard, editor, Reuters, archived from the original on 05 Jul 2022, Healthcare & Pharmaceuticals2 more examples
Dong Xuefeng, head of the Huangwei Township Central School in Sixian County, Anhui province, told a school gathering on Monday that Christmas was a disgrace to the Chinese people because of past humiliations inflicted on the nation by mostly Christian invaders.
[2018 December 26, Mandy Zuo, “Christmas linked to China’s past humiliation by foreign invaders in speech to primary schoolchildren”, in South China Morning Post, →ISSN, →OCLC, archived from the original on 20 Oct 2024, China/People & CultureMost of Anhui’s cases were identified in Suzhou’s Si County, where on Wednesday the authorities ordered its 760,000 residents to refrain from going out unless it was necessary.
2022 July 5, Zixu Wang, “Covid Outbreak Emerges in China’s Anhui Province”, in The New York Times, →ISSN, →OCLC, archived from the original on 05 Jul 2022, The Coronavirus Pandemic - historicalA surname from Mandarin.
Si6
- alternativeAlternative form of Xi.
Synonyms & antonyms
proper nounA county of Suzhou, Anhui, China.
More synonyms by meaning
nouna complete metric system of units of measurement for scientists; fundamental quantities are length (meter) and mass (kilogram) and time (second) and electric current (ampere) and temperature (kelvin) and amount of matter (mole) and luminous intensity (candela)
nouna tetravalent nonmetallic element; next to oxygen it is the most abundant element in the earth's crust; occurs in clay and feldspar and granite and quartz and sand; used as a semiconductor in transistors
nounthe syllable naming the seventh (subtonic) note of any musical scale in solmization
Synonym sets from Open English WordNet, CC BY 4.0.
Origin
si · noun
- LatinSāncte Iohannēs“Saint John (the Baptist)”
- Italiansi
- Middle Englishsi“seventh degree or note of Guido of Arezzo's hexachordal scales”
- Englishsi
From Middle English si (“seventh degree or note of Guido of Arezzo's hexachordal scales”), Italian si in the solmization of Guido of Arezzo, from the initials of Latin Sāncte Iohannēs (“Saint John (the Baptist)”) in the lyrics of the scale-ascending hymn Ut queant laxis by Paulus Deacon; thus, also an initialism of Sāncte Iohannēs.
More words from Middle English, Italian, Latin
Full word history & related roots →SI · proper noun
- FrenchSI“Système international d'unités”
- EnglishSI
Borrowed from French SI (“Système international d'unités”).
More words from French
Full word history & related roots →Si · proper noun
From clipping of various words beginning with the syllable /saɪ/.
Full word history & related roots →Translations
Arabic سِي
- سِي (sī)seventh note of a major scale
Basque si
- siseventh note of a major scale
Catalan si
- siseventh note of a major scale
Finnish ti, si
- tiseventh note of a major scale
- siseventh note of a major scale
French si
- siseventh note of a major scale
Hungarian ti
- tiseventh note of a major scale
Indonesian si
- siseventh note of a major scale
Italian si
- siseventh note of a major scale
Japanese シ
- シ (shi)seventh note of a major scale
Korean 시
- 시 (si)seventh note of a major scale
Polish si
- siseventh note of a major scale
Portuguese si
- siseventh note of a major scale
Russian си
- си (si)seventh note of a major scale
Spanish si
- siseventh note of a major scale
Vietnamese si
- siseventh note of a major scale
Rhymes & wordplay
Rhymes with si
All rhymes →Sounds the same
Cite this entry
si. (n.d.). In WatkinsX Dictionary. Retrieved November 2, 2026, from https://dictionary.watkinsx.com/word/si
“si.” WatkinsX Dictionary, https://dictionary.watkinsx.com/word/si. Accessed November 2, 2026.
WatkinsX Dictionary, s.v. “si,” accessed November 2, 2026, https://dictionary.watkinsx.com/word/si.
Source: si on Wiktionary, CC BY-SA 4.0.