1. a reduction by half; a fifty percent reduction

    半減する reduce by half

    • 人員を半減する
    • reduce [cut back] the staff by half
    • 不景気で輸出が半減した
    • Exports werecut in half [halved] by the recession.
    • 彼のいい加減な態度を見たら熱意が半減した
    • His irresponsible manner dampened my enthusiasm.
  1. 半減期〔放射能の〕a half-life; a half-value period