also: だいい
noun
captain (Army/USMC/USAF); lieutenant (Navy); flight lieutenant (RAF etc.)
Military rank; the exact equivalent depends on the service branch. The reading だいい was used by the Imperial Japanese Navy.
彼は陸軍の大尉に昇進した。
He was promoted to captain in the Army.
In the Navy, 大尉 corresponds to lieutenant.
From 大 (great) + 尉 (military officer rank). The reading だいい is a historical variant used by the Imperial Japanese Navy.