Si
A unisex Mandarin Chinese name meaning "fourth-born child" or "thinking".
Name Census estimates that about 165 living Americans carry the first name Si. It appears on both sides of the gender split, with 89.7% of registrations being male. The average person named Si today is around 30 years old, and the year with the single highest number of Si births was 2013 (15 babies).
This page is the full Name Census profile for Si. Below you will find a gender breakdown showing how the name splits between male and female registrations, a year-by-year popularity chart stretching back to 1880, decade-level totals, the top US states for this name, its meaning and etymology, and a set of frequently asked questions with data-backed answers.
For a British comparison, Name Census UK has a UK baby-name profile for Si with official rankings and popularity over time.
People living today
165
~ 1 in 2,077,299 Americans
Peak year
2013
15 babies that year
Average age
30
years old
2017 SSA rank
#12,008
Tracked since 1927
Census
Si in the 2020 Census
The 2020 Census recorded 2,486 people with the first name Si, which placed it at #6,449 in the published first-name tables. This is a snapshot of people who already had the name at the time of the Census.
The SSA sections elsewhere on this page answer a different question: how often parents gave the name to babies over time. The "people living today" figure on this page is different again: it is a current estimate built from SSA birth records and age-based survival rates, so the two numbers are not expected to match exactly.
2020 Census rank
#6,449
National first-name rank
People counted
2.5K
2,486 in the published race/origin table
Per 100,000
0.8
People with this name in 2020
Largest reported group
Asian and Pacific Islander
83.5% of people with this name
Demographics
Ancestry and ethnicity for Si
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Si is Asian/Pacific Islander at 83.5%. The next largest groups are White (10.8%) and Black (2.5%). These figures describe the people who had the name in 2020, not any inherent property of the name itself.
The bar chart below shows how people with the first name Si described their own race and ethnicity on the 2020 Census form. The Census Bureau groups responses into six broad categories: White, Black or African American, Hispanic or Latino, Asian and Pacific Islander, American Indian and Alaska Native, and Two or More Races. When a category has too few respondents for a given name, the Bureau suppresses the figure to protect individual privacy, which is why some names show fewer than six slices.
Percentages are shown so the breakdown is easy to read across every published category. Because the 2020 Census first-name file also includes raw headcounts for each group, Name Census can show those alongside the percentages in the legend and hover tooltip.
Keep in mind that these are self-reported numbers. A first name does not determine a person's race or ethnicity, and the distribution you see here reflects the specific population who happened to carry the name Si at the time of the 2020 Census, not any inherent property of the name itself.
- Asian and Pacific Islander83.5% · 2,077
- White10.8% · 269
- Black or African American2.5% · 61
- Hispanic or Latino1.8% · 44
- Two or more races1.0% · 26
- American Indian and Alaska Native0.4% · 9
Gender
Gender distribution for Si
Si leans heavily male at 89.7% of total registrations, but 19 girls have also been registered with the name over the years, giving it a small but present crossover presence.
Si as a male name
- Ranked #12,008 in 2017
- 6 male births in 2017
- Peak: 2013 (15 births)
Si as a female name
- Ranked #13,186 in 2011
- 8 female births in 2011
- Peak: 2011 (8 births)
2020 Census snapshot
The 2020 Census sex table shows Si on both sides of the split. Of the 2,488 people counted with this name, 1,507 were male (60.6%) and 981 were female (39.4%).
Popularity
Si: popularity over time
The SSA tracks Si from the 1920s through to the 2010s, spanning 9 decades of birth certificate data. The biggest single decade for the name was the 2010s, with 47 total registrations. The name continues to be given at rates close to its all-time high, suggesting it has not yet fallen out of fashion.
Babies born per year
Decades
Si by decade
The table below breaks the full SSA timeline into ten-year windows. Each row shows how many male and female babies were given the name Si during that decade, along with a combined total. This is useful for spotting eras where the name surged or retreated.
Geography
Where Sis live
Origin
Meaning and history of Si
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."
People
Si + last name combinations
How many people share a full name with Si as the first name? Click a combination below to see the estimate, or search any pairing.
Related
Other names starting with S
Other first names starting with S with a similar number of bearers.
FAQ
Si: questions and answers
How many people in the U.S. are named Si?
Name Census puts the figure at roughly 165 living Americans. We arrive at this by taking every SSA birth registration for Si going back to 1880 and adjusting each cohort for expected survival using CDC actuarial life tables. The result is an age-weighted living-bearer count, not a raw birth total. That works out to about 1 in 2,077,299 US residents.
Is Si a common name?
We classify Si as "Very Rare". It ranks above 71.6% of all first names in the SSA dataset by living bearers. Across the full history of the data, 185 babies have been registered with this name.
When was Si most popular?
The single biggest year for Si was 2013, when 15 babies received the name. The fact that the average living Si is about 30 years old gives you a rough sense of which era contributed the most bearers who are still alive today.
How common was Si in the 2020 Census?
The published 2020 Census first-name tables recorded 2,486 people with the name Si, or 0.82 per 100,000 residents. That placed it at #6,449 in the national Census ranking for first names.
Why is the Census count different from the living estimate?
Because they measure different things. The Census figure is a count of people who had the name Si in 2020. The living estimate aims to answer a current question instead: how many people with the name are alive today, based on SSA birth records and age-based survival rates. Since one number is a 2020 snapshot and the other is a present-day estimate, they are not expected to be identical.
What does the Census say about the gender split for Si?
The 2020 Census sex table shows Si on both sides of the split. Of the 2,488 people counted with this name, 1,507 were male (60.6%) and 981 were female (39.4%). The Census view is a snapshot of people living with the name in 2020, while the SSA section above tracks births across time.
What does the Census say about the background of people named Si?
In the 2020 Census race and Hispanic-origin table, the largest reported group for people named Si is Asian/Pacific Islander at 83.5%. The next largest groups are White (10.8%) and Black (2.5%). These figures describe the people who had the name in 2020, not any inherent property of the name itself. The percentages in the chart above come from self-reported race and Hispanic-origin responses in the 2020 Census.
Which group reports the name Si most often in the Census?
Asian/Pacific Islander is the largest reported group for people named Si in the 2020 Census, accounting for 83.5% (2,077 people in the published table).
Why can the Census sex total and race total differ slightly?
The Census Bureau published separate 2020 tables for sex and for race/Hispanic origin, and the released figures can differ slightly because of privacy protection in the public files. That is why this page treats the gender section and the race/origin section as two related snapshots instead of forcing them into one identical total.
Does every first name have Census demographic data?
No. The public Census first-name release only includes names that met the Bureau's publication rules, so many rarer names in the SSA files have no Census demographic snapshot. When that happens, the SSA trend, gender history, and state sections still appear, but the 2020 Census demographic sections are omitted.
What does the SSA popularity chart show?
The chart tracks births, not the number of people alive with the name today. Each point shows how many babies were given the name Si in that year. That makes it useful for spotting when the name rose, peaked, or faded.
Is Si a male name?
Yes, 89.7% of people registered as Si in the SSA data are male. You can see the full per-sex comparison in the gender distribution section above, which includes the latest year rank, birth count, and peak year for each sex.
Is Si still being used today?
Yes. The SSA still recorded Si in 2024, and the page above shows its latest-year rank where available. A name can be well past its peak and still remain in steady use, especially if it built up a large population over earlier decades.
Why can a name have a lot of living bearers even if it is not trendy now?
Because living-bearer counts and current baby-name popularity measure different things. A name like Si can build up a very large population over many decades, even if fewer parents are choosing it now than they did at its peak.
Where does this data come from?
First-name figures come from the Social Security Administration's national baby name files, which cover every name on a birth certificate from 1880 to 2024. Living-bearer estimates layer in CDC actuarial life tables broken out by sex to account for mortality. The population baseline (342,754,338) is the Census Bureau's latest national estimate. You can read the full calculation on our methodology page.
How many people are called Si?
For a faster, more casual read, check HowManyOfMe.org — our sister site built around that single question.