lower deck

countable broadly uncountable

Japanese Meaning

船倉のすぐ上にある甲板 / 船の乗組員のうち、士官ではない下級乗組員（下級船員）

Before the voyage, the crew stowed the barrels on the lower deck to keep the cargo hold clear.

出航の前に、乗組員は船倉を空けておくために樽を船倉の直上にある甲板に積み込んだ。

Sense（1）

(countable, nautical) The deck of a ship immediately above the hold

Sense（2）

(uncountable, nautical, by extension) Those members of a ship's company who are not officers.

lower decks

（ plural ）