A bay or inlet formed where the sea extends inland; a kind of cove or gulf (often with particular tidal/currents).
この入り海は潮の流れが速いので、小型船は注意が必要だ。
The currents in this inlet are strong, so small boats need to be careful.
漁師たちは入り海で豊富な魚を獲ることで知られている。
Fishermen are known for catching abundant fish in the inlet.