東海
とうかい Tōkai region (of Honshu; incl. Aichi, Shizuoka, Mie and southern Gifu prefectures)
Why it means this
東 (east) + 海 (sea) — the Tōkai region along Honshu's Pacific coast; also an old name for the sea east of Japan.
Breakdown
Each character links to its full entry — origin story, stroke order, and readings.