scheduled bus; fixed-route bus
Refers to a bus that runs on a set timetable and route, as opposed to a chartered or on-demand bus. Often contrasted with 路線バス (route bus) in some contexts, but essentially synonymous.
See also: 路線バス
There are only three scheduled buses a day in this village.
Compound of 定期 (fixed period, scheduled) and バス (bus).