Navy
noun, の adjective
The sea army are the branch of the military that has boats and does ocean/sea things. What's that? The navy.
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
僕のおじいちゃんは、海軍の軍人だったそうです。
I heard that my grandfather was a sailor in the Navy.
これは、第二次世界大戦の時に、イギリスの海軍が使っていたものです。
This is something used by the British Navy during World War II.
日本の海軍は、週に一度カレーを食べていました。このカレーは、今では「海軍カレー」としてレトルトでも売られています。
The Japanese Navy used to eat curry once a week. This curry is now sold as "Navy Curry" even in retort pouches.