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Home › Baby Names Directory › Castor

Castor

♂ Boy

Pronounced KAS-ter /ˈkæs.tər/High

Meaning: From Greek Kastor, variously 'a beaver' and 'one who excels / shines' — one of the Gemini twins (Castor and Pollux); we note the mythLow

In 30 seconds: A beaver; one who excels; shining: Castor is Greek. Crisp, classic, and warm.
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Origin LowGreek
MeaningFrom Greek Kastor, variously 'a beaver' and 'one who excels / shines' — one of the Gemini twins (Castor and Pollux); we note the myth
U.S. rank (2025)#4734 ↗ Rising
2025 U.S. births21 boys (0.00% of U.S. boys)
Peak year2016
Total births (all-time)≈ 387

Popularity in the U.S. · SSA data

peak 201619982025

U.S. births per year (Social Security Administration, 1880–present). Pink marker = peak year.

SSA data updated May 2026. How we source & verify this data.

History & Origin

Castor comes from Greek Kastor, variously 'a beaver' and 'one who excels / shines' — one of the heavenly twins, Castor and Pollux, and a bright star in Gemini (we note the myth). A crisp, classic name (said 'KAS-ter'; nickname Cas).

In the U.S. it appears thinly. Rare, one-who-excels-and-shines at the root, and classic.

Did you know? Castor is variously 'a beaver' and 'one who excels / shines' in Greek — one of the Gemini twins (Castor and Pollux), and a bright star in that constellation — a crisp, classic name (we note the myth; said 'KAS-ter').
Overall data confidence 45%
References — Castor — myth noted

Variations

KastorCastore

Nicknames

Cas

Famous Bearers

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If you like Castor…

Cassius— a sound-neighbor classical boys' name
Orion— a fellow constellation/mythology boys' name
Leander— another Greek classical boys' name
Hector— another Greek name
Cyrus— shares Castor's Greek roots

Explore names like Castor

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Frequently Asked

What does the name Castor mean?

Castor is Greek, variously 'a beaver' and 'one who excels / shines' (a Gemini twin). We note the myth.

How do you pronounce Castor?

It's said KAS-ter /ˈkæs.tər/ — two syllables, stress on the first.

Is Castor a boy or girl name?

Castor is a boy's name.

How popular is Castor?

Castor is a rare name in the U.S.

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