How to say "factorial" in Japanese

• 階乗かいじょう
  nounThe established Japanese term for the mathematical factorial, the product of all positive integers up to a given number. Use this in mathematics, programming, and education; it is less common overall simply because the concept itself is specialized.
• ファクトリアル
  nounA katakana loanword covering the same mathematical sense of 'factorial'. It is less common than the native term and is seldom the word you want; 階乗 is normally preferred in mathematical writing.

For the mathematical sense of 'factorial', 階乗 is the usual Japanese term; 「ファクトリアル」 is a less common katakana alternative that also refers to the same mathematical concept.

Usage comparisons are AI-assisted and cross-checked by multiple models; for study reference only

• 階乗かいじょうfactorial
• ファクトリアルfactorial