lieutenant colonel; commander (navy)
Military rank. In the army/air force it corresponds to lieutenant colonel; in the navy it corresponds to commander.
He was promoted to lieutenant colonel last month.
He was promoted to lieutenant colonel in the army.
海軍の中佐が艦を指揮している。
A navy commander is commanding the ship.
His uniform bore the insignia of a lieutenant colonel.
少佐 and 中佐 look similar and are neighboring ranks (major/lieutenant commander vs. lieutenant colonel/commander), making them easy to confuse.
From 中 (middle) + 佐 (assistant, help), reflecting a mid-level officer rank in the traditional Japanese military rank system.