変更線(へんこうせん)

へんこうせん
noun
International Date Line
geography
1. International Date Line
The imaginary line at roughly 180° longitude that marks where the calendar date changes. Almost always appears in the full form 日付変更線(ひづけへんこうせん); the short form is used only after the full term has been established.
日付(ひづけ)変更線(へんこうせん)を越(こ)えた。
We crossed the International Date Line.
変更線(へんこうせん)を西(にし)に越(こ)えると日付(ひづけ)が進(すす)む。
Crossing the date line going west moves the date forward.
太平洋(たいへいよう)上空(じょうくう)で日付(ひづけ)変更線(へんこうせん)を通過(つうか)し、カレンダーが一日(いちにち)戻(もど)った。
We passed the International Date Line over the Pacific and the calendar went back one day.

Compound of 変更(へんこう) (change) + 線(せん) (line). The standalone word is uncommon; the standard term is 日付(ひづけ)変更線(へんこうせん) (date-change line).

Common collocations

  • 日付(ひづけ)変更線(へんこうせん): International Date Line (full term)
  • 変更線(へんこうせん)を越(こ)える: to cross the date line
  • 変更線(へんこうせん)を通過(つうか)する: to pass over the date line

Similar words

  • 経度(けいど): longitude — the angular measure, not the dateline itself
  • 時差(じさ): time difference — between time zones, related but distinct concept

Related Words

Compare: 経度(けいど) (longitude)
Compare: 時差(じさ) (time difference)
general
Added 2026.5.29 11:13 · Revised 2026.9.2 13:02
28000/28323_henkousen