Baby Name of the Day: Tamsin

The baby name Tamsin offers a fresh update to mid-century Tammy, with a crisp, British sensibility. 

Thanks to Fran for suggesting our Baby Name of the Day.

WHAT DOES THE NAME TAMSIN MEAN?

Classic boy’s name Thomas comes from Aramaic. It means twin. 

The name belongs to one of the apostles in the New Testament. Thanks to the 12th century martyr Saint Thomas a Becket, the name has long been among the most common choices in England. 

That’s before we factor in other figures from Thomas Jefferson to Tom Sawyer to Thomas Edison to Tommy Shelby. 

But what’s the feminine form of Thomas? 

Names like Tomasa and Tomine occur in some languages. Tommie could be the equivalent of Billie or Stevie. 

But the textbook answer? Thomasina.

Which is contracted to … yup, you guessed it! Tamsin. 

Or Tamzin or Tamsen or choose-your-preferred-spelling. 

But typically, it’s T-A-M-S-I-N. 

WHAT ABOUT TAMMY?

From 1966 through 1971, Tammy ranked in the US Top Ten. That puts it solidly it mom and grandma-name territory now.

It’s strongly tied to pop culture. A series of movies and television shows, starting with 1957’s Tammy and the Bachelor gave the name to a particular type of romantic heroine. Actress Debbie Reynolds starred as the title character and recorded the single “Tammy,” which became a hit.

Did Tammy come from Tamsin or Thomasina? Maybe … the movie character was Tambrey. Names like Tamara and Tamala also lagged behind Tammy in the US.

Other Tam- names include the Hebrew Tamar meaning “date palm.” And the Slavic form of Tamar, Tamara, is another option. Both seem a little more sophisticated and potentially less time-stamped than Tammy. 

Interestingly, even at peak-Tammy, Tamsin was scarcely heard in the US. 

FAMOUS FIGURES NAMED TAMSIN

Of course, Americans have never had a lot of places to hear the name. Most of the uses are British, including:

• In Thomas Hardy’s 1878 Return of the Native, one of the main characters is Thomasin, often called Tamsin. 
• In 1964, Disney’s The Three Lives of Thomasina adapted a 1957 novel about a rather special cat and her family.
• British actresses Tamsin Egerton and Tamsin Grieg come to mind, as do Tamzin Outhwaite and Tamzin Merchant. 
• Canada television series Lost Girl also gave us a Tamsin. 

HOW POPULAR IS THE NAME TAMSIN?

In the UK, the baby name Tamsin had a good run in the twentieth century. It’s particularly favored in Cornwall. But given the success of the boy’s name Thomas, it tracks that feminine forms of the name would be popular, too.

American parents never warmed to the name Tamsin.

In 1955, the name debuted in US popularity data, with five births. 

The baby name Tamsin peaked in 2017, with 27 births.

That’s still incredibly rare. 

Tamzin is even less familiar, and while Thomasina was once used in reasonable numbers, it’s all-but-forgotten now. 

In 2024, just seven girls were named Tamsin in the US.

All of that means the baby name Tamsin is vaguely familiar in a British import way – and almost astonishingly rare.

POLISHED RARITY

Overall, the baby name Tamsin strikes the right note between sweet and sophisticated. There’s a polish to this name. While it reads differently in the UK, in the US it’s a timeless rarity – maybe vaguely familiar, maybe subject to lots of spelling and correcting.

But it could wear very nicely on a daughter, a name in the key of Marlowe or Maren. 

What do you think of the baby name Tamsin?

This post was originally published on April 7, 2011. It was revised and re-posted on April 22, 2013 and again on February 24, 2026.