About the name Tamsin
Tamsin is a girl name with Cornish roots, meaning “Twin (Cornish form of Thomasina)”. It is related to Thomas, which is where the meaning comes from.
It has a unique feel. Fewer than 5 US babies of either sex received it in 2025, so it's very rare right now. Its peak year since 1940 was 2017. Since 2000, 100% of US babies named Tamsin were girls.
Etymology
A feminine form of Thomas, which comes from Aramaic, meaning “twin”.
Name meaning adapted from Wiktionary (“Tamsin”, “Thomas”) by Wiktionary contributors, CC BY-SA 4.0.
- US rank 2025
- Not ranked
- In 2015
- #6013
- Babies in 2025
- Under 5
Popularity of Tamsin, 1940–2025
Latest SSA data: 2025.
Popularity data: U.S. Social Security Administration national baby names (public domain; names given to at least 5 babies of one sex per year).
Hello, world
Tamsin
Your last name
born on your big day
7 LB 4 OZ · 20 IN
The Baby Kit
See Tamsin on a birth announcement
Birth announcements, shower invitations, nursery wall art and milestone cards, all personalized with Tamsin. Type your details once and print at home or at any print shop.
Nicknames for Tamsin
- Tammy
Names similar to Tamsin
Name meanings marked or linked “Wiktionary” are adapted from Wiktionary by Wiktionary contributors, CC BY-SA 4.0; each name page links its source entry.