四千(よんせん)

Formed as 四(よん) × 千(せん). Always よんせん, never しせん — し is avoided here because it is a homophone of 死(し) (death) and because よん is the default counting form before counters.

Sound changes in the thousands

• 三千(さんぜん): 3,000 — せん voices to ぜん
• 八千(はっせん): 8,000 — はち shortens to はっ
• 一千(いっせん): 1,000 — いち shortens to いっ
• 四千(よんせん), 五千(ごせん), 六千(ろくせん), 七千(ななせん), 九千(きゅうせん): regular

Common expressions

• 四千(よんせん)円(えん): four thousand yen
• 四千(よんせん)人(にん): four thousand people
• 四千(よんせん)メートル級(きゅう): in the four-thousand-metre class (of mountains)