Thomasin
Thomasin was given to 12 girls in 2025, #8,815 among girls’ names; 72 Americans have been recorded with it since 1963 (Social Security Administration, published May 2026).
Girls and boys together; gaps are years SSA did not record (fewer than 5 births).
Births of Thomasin by year: SSA national baby-name file, 1880-2025, published May 8, 2026. SSA’s notes on the data.
What does Thomasin mean?
Wiktionary, English section
Thomasin is “a female given name from Aramaic, a feminine form of Thomas.”
From Thomas + -in.
/ˈtɑm.əs.ɪn/
Meaning: Wiktionary, English section, as of Sep 25, 2026 (CC BY‑SA 4.0).
How popular is Thomasin?
#8,815 among girls’ names, 2025
Thomasin entered the girls’ rankings after 2015 and stood at #8,815 in 2025.
16 babies in 2023, the peak
Thomasin peaked in 2023, when 16 girls were given it, #7,216 among girls’ names. The 12 births of 2025 are 75% of that peak.
| Year | Births | Rank | Per million girls |
|---|---|---|---|
| 2025 | 12 | #8,815 | 7.5 |
| 2024 | 7 | #13,349 | 4.3 |
| 2023 | 16 | #7,216 | 10.0 |
| 2022 | 9 | #11,160 | 5.5 |
| 2021 | 12 | #8,928 | 7.3 |
| 2020 | 6 | #14,934 | 3.7 |
| 1971 | 5 | #9,521 | 3.0 |
| 1963 | 5 | #7,562 | 2.6 |
Ranks and shares: girls’ names in each year’s SSA file; share of all girls SSA recorded that year.
Is Thomasin a boy’s or a girl’s name?
Thomasin has been recorded only for girls: SSA lists no boys with the name in 8 years of records (it lists a name only in years with 5 or more babies of a sex).
Girls and boys named Thomasin: the SSA national file counts each sex separately.
How many people are named Thomasin, and how old are they?
An estimated 71 Americans named Thomasin and born in the U.S. are alive in 2026, too few to state an age range. An estimate from SSA’s births and life tables, not a count.
Living estimate: SSA births carried forward with the survival rates in SSA’s cohort life tables (2024 Trustees Report) for each birth year and sex. How the estimate is made.
Names spelled alike
Of these 2 names spelled alike, given to 2,306 babies since 1880, Thomasin is the second most given (3.1% of them).
Spelled alike: names in the SSA national file with the same pattern of letters and sounds and at most two letters apart, and Wiktionary’s listed forms; births since 1880 and in 2025, and each name’s peak year, from the SSA national file, published May 8, 2026. Some are separate names, not spellings of one.
Names that rose and fell in the same decades as Thomasin
Names whose births rose and fell across the same decades, measured on each decade’s share of births.
Similar histories: each decade’s share of births, from the SSA national file, 1880-2025, published May 8, 2026. SSA’s notes on the data.
More about Thomasin and names like it
- Compare Thomasin and ThomasineBirths, ranks, peak and the living estimate side by side.
- The most given names of the 2020sThomasin peaked in 2023.
- The top names of 2023The year the most babies were named Thomasin.
- Names starting with TMost given first.