noun
Military term for a reinforced protective structure, often used for aircraft or personnel.
旧日本軍の掩体壕が今も島に残っている。
Old Japanese military bunkers still remain on the island.
防空壕 is a more general air-raid shelter, while 掩体壕 specifically refers to a military bunker or revetment, often for aircraft.
Compound of 掩体 (えんたい, 'cover' or 'shelter') and 壕 (ごう, 'trench' or 'dugout'). The exact historical derivation is uncertain; the spelling is conventionally associated with military fortifications.