A Japanese form of ritual suicide, the term "seppuku" derives from the two Sino-Japanese roots setsu 切 ("to cut", from Middle Chinese tset) and puku 腹 ("belly", from MC pjuwk). It is also known as harakiri (腹切り, "cutting the belly"),[4] a term more widely familiar outside Japan, and which is written with the same kanji as seppuku, but in reverse order with an okurigana. In Japanese, the more formal seppuku, a Chinese on'yomi reading, is typically used in writing, while harakiri, a native kun'yomi reading, is used in speech. Ross notes,

It is commonly pointed out that hara-kiri is a vulgarism, but this is a misunderstanding. Hara-kiri is a Japanese reading or Kun-yomi of the characters; as it became customary to prefer Chinese readings in official announcements, only the term seppuku was ever used in writing. So hara-kiri is a spoken term, but only to commoners and seppuku a written term, but spoken amongst higher classes for the same act.[5]

The word jigai (自害?) means "suicide" in Japanese. The modern word for suicide is jisatsu (自殺?). In some popular western texts, such as martial arts magazines, the term is associated with suicide of samurai wives.[6] The term was introduced into English by Lafcadio Hearn in his Japan: An Attempt at Interpretation,[7] an understanding which has since been translated into Japanese.[8] Joshua S. Mostow notes that Hearn misunderstood the term jigai to be the female equivalent of seppuku.[9]