liner; regularly scheduled ship
Refers to a ship that operates on a fixed route and timetable, such as a passenger liner or cargo vessel with regular service.
この港には毎週、定期船が入港する。
A liner calls at this port every week.
定期船の運航スケジュールを確認してください。
Please check the schedule of the regularly scheduled ship.
定期船 specifically means a ship that runs on a fixed schedule, while 船便 more broadly refers to any ferry or steamer service.
ocean liner
Compound of 定期 (regular schedule) and 船 (ship). The term is straightforward and modern.