Kosei
Meaningoften bright star · Japanese
Kosei is a Japanese boy name often meaning “bright star”. In Japan, parents often choose a name as much for the kanji characters behind it as for its sound, so the same name can carry several shades of meaning. A meaning like this gives a child something to grow into, and a good story to tell when someone asks about their name. It sounds soft and friendly, it's easy to spell and quick to call across a playground, and it pairs well with middle names of almost any length.
Did you know?
- GenerationKosei peaked in 2008, which makes it a Gen Z name. The typical Kosei you'd meet today is about 17 years old.
- HistoryKosei first shows up in US birth records in 2000, the first year at least 5 babies got it. That makes it a fairly new name, younger than many of today's parents.
US births per million boys, 2000–2025
Similar names
Save adds it to your list. Vote moves it up the top voted names.
Popularity: U.S. Social Security Administration (babies with 5+ births per year).
About the name Kosei
Kosei is a boy name of Japanese origin meaning “often bright star”. Its two syllables give it an easy rhythm, and the open vowel at the end makes it sound soft and warm. It's a fresh, modern name that only arrived in US birth records in recent decades. It's rarely heard today, so it stands out while still being a real, established name.
Origin:Japanese names
More Japanese boy names
- Unisex name: Asa · healer
- Unisex name: Rio · river
- Unisex name: Akari · light, brightness
- Boy name: Kenzo · often healthy third son
- Boy name: Kenji · often strong second son
- Unisex name: Ren · often lotus
- Unisex name: Zen · meditation
- Unisex name: Mars · god of war
Questions about the name Kosei
What does the name Kosei mean?
Kosei means “often bright star” and comes from Japanese. Names built around “star” have been loved for generations, and give a child a meaning worth sharing when someone asks about their name. Other boy names with a similar meaning include Dhruv (“steadfast, pole star”), Tariq (“morning star”), Star (“star”) and Astro (“star”).
What is the origin of the name Kosei?
Kosei is Japanese in origin. Other Japanese names to consider are Asa (“healer”), Rio (“river”), Akari (“light, brightness”) and Kenzo (“often healthy third son”).
Is Kosei a boy or girl name?
Kosei is a boy name.
How popular is the name Kosei?
Kosei is rare: fewer than 5 US boys got it in 2025, and it was last given to 5 or more in 2020. It peaked at #8,324 in 2008, so it's a name with history that few kids share today.
What names are similar to Kosei?
If you like Kosei, you might also like Dhruv, Tariq, Star and Astro.
What should I know before naming my baby Kosei?
Kosei is a Japanese boy name often meaning “bright star”. In Japan, parents often choose a name as much for the kanji characters behind it as for its sound, so the same name can carry several shades of meaning. A meaning like this gives a child something to grow into, and a good story to tell when someone asks about their name. It sounds soft and friendly, it's easy to spell and quick to call across a playground, and it pairs well with middle names of almost any length. Say it out loud with your last name and any middle names you're considering, and check the initials it makes.