Does a lane always have to be marked with a road marking to be considered as a lane?

A lane is a part of a roadway indicated by longitudinal road markings or, if road markings do not exist, is sufficiently wide for a four-wheeled vehicle.

If there is room for two four-wheeled vehicles to drive next to each other then there do not have to be any longitudinal road markings (for example, a centre line) in order for the roadway to be considered as having two lanes.