The highest point; the flatland.
Ex: Summit is to mountain/hill as _____ is to plateau.
Would summit just be acceptable in itself?
By definition, "a plateau" consists of relatively flat terrain that is raised significantly above the surrounding area. If any part of a plateau is raised significantly to form a peak, it won't be considered a part of it. In a nutshell, there are no significant peaks on a plateau.
- "plateau" or "high plain" or "tableland" - an elevated, comparatively level expanse of land. TFD
Yes, summit and peak are perfectly understood with respect to mesas and plateaus. And many of them are anything but flat on top. They tend to be craggy and tilted.
Black Mesa Summit -
The highest point in Oklahoma at 4,973 feet, Black Mesa Summit can be reached with a scenic 4.2-mile hike across landscape unknown in other parts of the Sooner State.
Uncompahgre Pleateau - Horsefly Peak
The Plateau rises from 4,600 feet (1,400 m) at Gateway to over 10,300 feet (3,100 m) at the top of Horsefly Peak. The summit is relatively flat with an average elevation of 9,500 feet (2,900 m) that runs southeast to northwest. The summit drops off quickly on the west side and more gradually slopes downward on the east side.