Girl · #8,930 in 2026

Thomasin

Thomasina, Thomasine, or Thomasena is the feminine form of the given name Thomas, which means "twin". Thomasina is often shortened to Tamsin. Tamsin can be used as a name in itself; variants of Tamsin include Tamsyn, Tamzin, Tamsen, Tamzen, Tammi, Tamzie and Tamasin. The version "Tamsin" is especially popular in Cornwall and Wales. Along with Tamara it is the ancestor of "Tammy".

Current Rank
#8,930
Peak Rank
#6,590 (2023)
Total Babies
80
5-Yr Trend
Stable
1963
First Year
2026
Last Year
2023
Peak Year
#6590
Peak Rank
80
Total Count
9
Years Active

Meaning & Origin of Thomasin

What this name means, where it came from, and how it has traveled across cultures.

Thomasina, Thomasine, or Thomasena is the feminine form of the given name Thomas, which means "twin". Thomasina is often shortened to Tamsin. Tamsin can be used as a name in itself; variants of Tamsin include Tamsyn, Tamzin, Tamsen, Tamzen, Tammi, Tamzie and Tamasin. The version "Tamsin" is especially popular in Cornwall and Wales. Along with Tamara it is the ancestor of "Tammy".

Source: Wikipedia (CC BY-SA 3.0). Read more →

The Story of Thomasin

Thomasin first appeared in U.S. Social Security Administration records as a baby girl name in 1963, with 5 babies given the name that year. Its peak popularity came in 2023, when 16 Thomasins were born — ranking #6,915 that year. As of 2026, Thomasin ranks #8,930 for baby girls with 10 births, with steady use. In total, more than 80 Thomasins have been born in the U.S. since records began in 1880, spanning the 1960s through the 2020s.

Popularity Over Time

Popularity by State

ME
WA
MT
ND
MN
WI
MI
NY
VT
NH
MA
OR
ID
SD
IA
IL
IN
OH
PA
NJ
CT
RI
CA
NV
WY
NE
MO
KY
WV
VA
MD
DE
DC
UT
CO
KS
AR
TN
NC
SC
AK
AZ
NM
OK
LA
MS
AL
GA
HI
TX
FL
Top 10
11-50
51-100
101-500
500+
No data

Where is Thomasin most common?

Predicted country distribution based on naming patterns globally.

  • Switzerland
    55%
  • Austria
    18%
  • Czech Republic
    10%
  • France
    8%
  • United States
    8%

Source: Nationalize.io . Probabilities are global naming-pattern estimates, not strict counts.

Names that sound like Thomasin

Phonetically similar names — useful when Thomasin is the vibe but a different syllable count or letter feel might suit better. Linked entries have a profile on Peek a Name.

Source: Datamuse . Phonetic similarity ranking, not curated.

Frequently Asked Questions about Thomasin

What does the name Thomasin mean?
Thomasina, Thomasine, or Thomasena is the feminine form of the given name Thomas, which means "twin". Thomasina is often shortened to Tamsin. Tamsin can be used as a name in itself; variants of Tamsin include Tamsyn, Tamzin, Tamsen, Tamzen, Tammi, Tamzie and Tamasin. The version "Tamsin" is especially popular in Cornwall and Wales. Along with Tamara it is the ancestor of "Tammy".
How popular is Thomasin in 2026?
In 2026, Thomasin ranks #8,930 among girls' names in the U.S., with 10 babies given the name that year.
When was Thomasin most popular?
Thomasin reached its peak popularity in 2023, ranking #6,590 that year with 16 babies given the name.
Is Thomasin a unisex name?
In U.S. Social Security records, Thomasin is primarily a girl's name. We don't have meaningful data for it as a boy's name.
What names go well with Thomasin?
Names that share a similar style or popularity range with Thomasin include Aldrina, Angelar, Balynda. These pairings are based on rank proximity and naming era in U.S. data.

Similar Names

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Aldrina
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Angelar
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Balynda
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Bernda
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Berrie
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About the name Thomasin

Thomasin is a girl baby name tracked by the U.S. Social Security Administration. It first appeared in SSA records in 1963 and has accumulated 80 births in the dataset. Thomasin's peak popularity came in 2023 when it ranked #6,590. Use the chart and map above to compare Thomasin's trajectory across years and U.S. states, or browse the related names section to discover similar choices.

Continue exploring

Data sources

  • Birth statistics (counts, ranks, years 1880–2026) — U.S. Social Security Administration . Predictions for years not yet released by SSA are computed by Peek a Name from historical trends; we update with official data as soon as it ships.
  • Etymology, cultural origins, and related forms — Behind the Name (used under their public API terms).
  • Meaning prose and editorial summary — Wikipedia article extracts, licensed under CC BY-SA 3.0 .
  • Predicted nationality distribution — Nationalize.io .
  • Phonetically similar names — Datamuse .

Peek a Name aggregates and presents the above data for informational purposes. Statistical predictions and external attributions are clearly labelled where shown; we make no guarantee of accuracy beyond what each source provides.