- A day gained or lost when crossing the International Dateline at the 180th meridian.
Probably earlier than the 17th century. From Greek, hoi antipodes. Meaning opposite.
You add a day when crossing the International Dateline heading west and subtract a day when heading east. For example, if today is Wednesday July 1, and you crossed the line heading west, then it would be Thursday July 2. In another example, when I departed Narita airport in Japan around 5pm on, say, Wednesday June 30, then I would arrive in Portland, Oregon around 8am on the same day (by which time it would already be the next day in Japan). The jet lag is ferocious, though!
Rogers, J.G. (1985). Origins of Sea Terms. Mystic, CT: Mystic Seaport Museum.