ユーレカ

noun

eureka

An exclamation of discovery or sudden insight, borrowed from Greek. Used in Japanese as a noun or interjection, often in intellectual or playful contexts.

from Greek heureka

• 彼かれは問もん題だいの答こたえを見みつけて、「ユーレカ！」と叫さけんだ。

  He found the answer to the problem and shouted, "Eureka!"