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; the short form is used only after the full term has been established.
日付変更線を越えた。
We crossed the International Date Line.
変更線を西に越えると日付が進む。
Crossing the date line going west moves the date forward.
太平洋上空で日付変更線を通過し、カレンダーが一日戻った。
We passed the International Date Line over the Pacific and the calendar went back one day.
Compound of 変更 (change) + 線 (line). The standalone word is uncommon; the standard term is 日付変更線 (date-change line).
COMMON COLLOCATIONS:
- 日付変更線: International Date Line (full term)
- 変更線を越える: to cross the date line
- 変更線を通過する: to pass over the date line
SIMILAR WORDS:
- 経度: longitude — the angular measure, not the dateline itself
- 時差: time difference — between time zones, related but distinct concept