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Thomasin

#8,815 in 2025Girls' name

Thomas with the suffix -in

Thomasin has been given to 72 babies in the U.S. since 1963. In 2025 it ranked #8,815 of 17,293 girls’ names in use. Its peak year was 2023, with 16 recorded.

Babies named Thomasin, 2025

1 in 276,000

Thomasin over time, 1880–2025

Girls
0510152018801900192019401960198020002020

Based on births in the U.S. Babies given the name each year. Hover the chart — or focus it and use the arrow keys — for any year. Gaps mean the name was given fewer than 5 times that year; these counts are unpublished.

Thomasin: meaning, origin, and history

Thomas with the suffix -in

Aramaic

What Thomasin means

Thomasin is formed from Thomas with the suffix -in.

Origin, language, and formation

Thomasin is used in English. Its origins include Aramaic.

Related names and everyday forms

Related names include Thomas.

Pronunciation and spelling

In English, Thomasin is pronounced /ˈtɑm.əs.ɪn/.

American usage and historical context

In the United States, 72 girls were recorded with the name Thomasin between 1963 and 2025. Its highest annual count was 16 in 2023; its best national rank was #7,216 in 2023.

Over 5 years its rank rose, from #14,934 in 2020 to #8,815 in 2025.

Sources & methodologyReferences, data & attribution

Meaning, origin, and language notes draw on the references below.

American popularity figures use published Social Security Administration records for this exact spelling. Counts below five for a name, sex, and year are omitted.

Wiktionary material is available under CC BY-SA 4.0.

How common is Thomasin?

Everything below is computed from the 2025 data — the most recent year available.

Among all babies, 2025
1 in 276,000
12 of 3,315,165 births
Among girls only
1 in 134,000
<0.01% of girls
Rank, 2025
#8,815
of 17,293 girls’ names in use
Coin-flip room size
191,493 kids
Even odds of a second one

Where Thomasin sits on the popularity scale

Rarest published (5 a year)#1 — Olivia (13,544)

Chance at least one other child shares the name

If the other children were drawn at random from the 2025 national name distribution. Real classrooms cluster by region and community, so treat these as a floor, not a ceiling.

Class of 20Under 1%
Class of 30Under 1%
Grade of 100Under 1%
School of 500Under 1%

Put another way: gather 191,493 children born in 2025 and it's an even bet that one of them is another Thomasin. In a class of 30 the chance is Under 1%.

When Thomasins were born

Half of everyone ever recorded as Thomasin was born before 2022 — so the typical Thomasin is around 3 today.

Median birth year
2022
About 3 years old
Biggest decade
2020s
86.1% of all use
Born in the last 25 years
86.1%
A modern name
Recorded since 1950
72
People you could plausibly meet
Choose a decade

2020s — 86.1% of all recorded uses (62).

Is Thomasin rising or falling?

Rank movement and count movement can disagree — the number of distinct names in use keeps growing, so a name holding a steady count still slides down the list. Both are shown.

Rank vs 1 year ago
+4,534
Places climbed
Rank vs 5 years ago
+6,119
Places climbed
Rank vs 10 years ago
—
Not ranked then
Births vs 10 years ago
—
Not published both years
Share of its own peak
75.0%
Peak was 2023 (16)
Years since peak
2
Years
Year-to-year steadiness
Volatile
66.1% average annual change
Best rank ever
#7,216
2023

Spellings of Thomasin

Thomasin is not the most common spelling — Thomas is, with 55.4% against Thomasin's 0.47%.

Grouped by closeness of spelling (up to two letter changes), same sex, with a floor on all-time use. It catches Sophia/Sofia and Aiden/Ayden, and misses spellings that sound alike but look different, like Sean and Shawn.

Thomasin around the world

Where Thomasin ranks in official birth records elsewhere in the world. Rankings only — the number of births isn’t comparable between places, so it isn’t shown.

  • England & Wales
    1998–2023
    #5,688
    in 2023

Popularity data from Office for National Statistics. ONS data under Open Government Licence v3.0.

Thomasin by the numbers

The raw record for each sex the name is used for.

As a girl's name

Rank in 2025
#8,815
Trend vs 5 yrs ago
Up 6,119
Best rank ever
#7,216
2023
Peak year
2023
16 that year
First recorded
1963
Last recorded
2025
All-time count
72
Count in 2025
12

Names similar to Thomasin

Matched on shared beginnings and endings, similar length, and comparable popularity.

ThompsonThomeshaThomaseniaThomaseneThomasaMahasinThomishaMadisinAllysinMadasinThondaAddysinAddisinThordisBlessinThomiaThomasenaKarsinAdysinMadysinThorineThomesaThomasitaThomara

Sibling names for Thomasin

Names from the same era and popularity tier — the two things that make a sibling set feel deliberate — skipping lookalike spellings and shared initials.

Explore around Thomasin

Top names of 2023, Thomasin's peak yearThe 2020s in fullOther names that peaked in 2023Girls' names starting with T