A clock-face schedule is a timetable in which public means of transport run in consistent intervals; by extension, extension programs lines to converge on hubs at a given point of the clock-face.
A clock-face schedule is a timetable in which public means of transport run in consistent intervals, as opposed to timetable that is purely driven by demand and with irregular headways. By extension, extension programs lines to converge on hubs at a given point of the clock-face.