再発

• Reading: さいはつ
• Romaji: saihatsu
• Kanji breakdown: 再 (sai) — again, re-, twice; 発 (hatsu) — emit, occur, depart
• Pronunciation: /sa.i.ha.tsɯ/

Meaning

Relapse; recurrence; return. When a disease or condition comes back after a period of improvement.

A noun and suru-verb (intransitive) used primarily in medical contexts to describe the return of an illness that was previously in remission or under control. Common with cancer (がんの再発), infections, and chronic conditions. Also used outside medicine to describe the recurrence of problems or incidents (事件の再発防止, preventing recurrence of incidents).

Examples

1. がんが再発しないように、定期的に検査を受けている。 I get regular check-ups to make sure my cancer doesn't come back.
2. 治療をやめたら、病気が再発してしまった。 When I stopped treatment, the illness relapsed.
3. 再発を防ぐためには、生活習慣の改善が大切だ。 To prevent a recurrence, it's important to improve your lifestyle habits.

Usage Guide

Context: medical, health, news

Tone: serious

Origin & History

From Sino-Japanese: 再 (sai, again/re-) + 発 (hatsu, occur/emit). Literally 'to occur again.'

Cultural Context

Era: Modern

Generation: All ages

Social background: Universal