NameCensus.

UK name, mostly girls

Si

A unisex Mandarin Chinese name meaning "fourth-born child" or "thinking".

For 2026, the newest official UK baby-name figures on this page are from 2018. That release is the current official benchmark rather than a forecast.

Also recorded as a boys' name in the UK, with 26 boys.

Si is mostly registered for girls in the UK records. People looking for Si popularity in 2026 should use the latest official release, which is 2018 in this profile. In that release it ranked #5666, with 3 babies registered with the name. Its strongest year in the published records was 2010, with 17 births.

This profile covers 77 England and Wales registrations across 14 recorded years from 1998 to 2018. The figures come from ONS England and Wales and NRS Scotland, so the page is a view of published baby-name registrations rather than a forecast or a live count of people using the name today.

The latest count is about 18% of the recorded peak, which gives a quick read on how the name has moved since its high point.

We estimate that about 80 living people in the UK are called Si. This uses published birth registrations from England and Wales, Scotland and Northern Ireland, then applies ONS national life tables to estimate how many are likely still alive. It does not forecast extra births for 2019 or 2026.

Key insights

  • Si ranked #5666 for girls in England and Wales in 2018, with 3 registrations.
  • The name peaked in 2010, when 17 girls were registered as Si.
  • Si ranks best in Scotland in the latest published regional snapshot for that area, where it placed #802 in 2010.
  • Si is also recorded for boys, but the girls side is the larger UK variant in these records.
  • About 80 living people in the UK are estimated to have Si as a first name, after adjusting past birth registrations with ONS life tables.
  • Across the England and Wales records shown here, 74.8% of Si registrations are for girls.

Latest rank (E&W)

#5666

2018

Births in 2018

3

Latest year

Peak year

2010

17 births

Estimated living

80

2026

Gender

Boy and girl registrations for Si

In England and Wales birth records, Si has been registered for both boys and girls. Across the years shown here, 25.2% of registrations are for boys and 74.8% are for girls.

These figures use the sex categories in the published baby-name files. They are useful for spotting how the name is used at registration, but they are not a live measure of gender identity or everyone living with the name today.

25% boys
75% girls
Boys26 (25.2%)Girls77 (74.8%)

Si registered for boys

  • Ranked #4,812 in 2017
  • 3 boys registered in 2017
  • Peak: 2006 (6 births)

Si registered for girls

  • Ranked #5,666 in 2018
  • 3 girls registered in 2018
  • Peak: 2010 (17 births)

Meaning

What does Si mean?

The name Si has its origins in ancient China, dating back to the Zhou Dynasty (1046–256 BC). It is a short form of the Chinese name Sishi, which means "beginning" or "start." The name was popular among the Chinese aristocracy and was often given to firstborn sons, symbolizing the start of a new generation.

One of the earliest recorded instances of the name Si can be found in the classic Chinese text, the Analects of Confucius (551–479 BC). The philosopher Confucius had a disciple named Si Shen Gong, who is mentioned in several passages as a devoted follower.

During the Tang Dynasty (618–907 AD), the name Si gained popularity among scholars and poets. One notable figure was Si Kongtu (648–726), a renowned calligrapher and painter whose works are still celebrated today.

In the realm of Chinese Buddhism, the name Si is associated with the monk Si Xianchi (629–702), who is revered for his contributions to the spread of Buddhism in China. He is known for his translations of Buddhist scriptures and his efforts to bridge the gap between Chinese and Indian Buddhist practices.

Moving forward to the Song Dynasty (960–1279), the name Si is linked to the famous statesman and poet Si Konglian (1008–1087). He served as a high-ranking official under several emperors and is renowned for his literary works, particularly his poetry.

Another prominent figure bearing the name Si is Si Tuozhuan (1300–1380), a general who served during the Yuan Dynasty (1271–1368). He is celebrated for his military prowess and his role in defending China against Mongol invasions.

While the name Si has its roots in ancient China, it has also been adopted by other cultures and languages over time. For example, in the Vietnamese language, the name Si is a variation of the name Thi, which means "poetry" or "literature."

Sourced from namecensus.com.

Popularity

Si over time

The chart below compares boys and girls registered as Si in England and Wales, from 1998 to 2018. Empty years are left out so rare names are not stretched across long periods where the published files do not show any registrations.

For Si, the clearest high point is 2010. The latest England and Wales figure is 3 births in 2018, compared with 17 at the peak.

Babies born per year

BoysGirls
0491317199820082018

Decades

Si by decade

Decade totals smooth out the yearly jumps and make it easier to see whether Si was a short-lived spike or a name that stayed in regular use. Average rank is calculated only from years where a published rank exists.

Decade Average rank Total births Years covered
2010s #4165 44 7
2000s #3995 28 6
1990s #2701 5 1

Geography

Where Si is most common

The bars show the latest published local birth counts for Si. They are useful for spotting where the name is showing up in real numbers, while the rank beside each bar shows how strongly it performs inside that region.

Si ranks best in Scotland in the latest published regional snapshot for that area, where it placed #802 in 2010.

Scotland
3

Across the UK

Si in Scotland and Northern Ireland

Scotland (NRS)

#802 in 2010

1 years of NRS records, 3 total registered

Notable bearers

Famous people named Si

  • Si Adams

    candidate in the 2024 United Kingdom general election

Related

Names similar to Si

FAQ

Si: questions and answers

How popular is the name Si in the UK right now?

In 2018, Si was ranked #5666 for girls in England and Wales, with 3 births registered.

When was Si most popular?

The peak year on record was 2010, with 17 babies registered as Si in England and Wales.

What is the meaning and origin of Si?

A unisex Mandarin Chinese name meaning "fourth-born child" or "thinking".

How many people are called Si in the UK?

A total of 77 babies have been registered as Si across the 14 years of ONS England & Wales records shown here, plus 3 more in Scotland.

Where is Si most common?

In the latest published local rankings, Si ranks best in Scotland, where it placed #802 in 2010. The regional bars on this page use birth counts, so they also reflect the size of each region.

Which records is this page based on?

The England and Wales timeline uses ONS baby-name records. Scotland figures come from NRS and Northern Ireland figures come from NISRA. Counts are registrations in published baby-name files. The living estimate uses those birth registrations with ONS national life tables.