1.
mainland
The main body of a country's territory, as opposed to islands or overseas territories.
本土 means the main landmass of a country, as opposed to islands, overseas territories, or outlying areas.
Japan context
In Japan, 本土 usually refers to the four main islands (本州, 北海道, 九州, 四国) as opposed to 沖縄 or 離島 (remote islands). This usage is especially common in Okinawa, where people distinguish between 本土 and their own islands.
Common patterns
Related words
Related Words
Related:
本州 (Honshu)
Related:
離島 (remote island)
Related:
内地 (mainland)
Related:
島民 (islander)