This is the 9677th most frequent Japanese word.
船長
Ship captain.
船長 refers to the person holding the role of captain of a vessel.
船長が航海の指示を出した。
The captain gave orders for the voyage.
船長 here signifies the leader or person responsible for the ship.
船長は船員たちを励ました。
The captain encouraged the crew members.
船長 in this case indicates the subject whose leadership and experience are emphasized.