High flat region (7)
I believe the answer is:
plateau
(Other definitions for plateau that I've seen before include "Level outcrop of land" , "Elevated flatland" , "tray that is ornamented" , "Flat-topped height" , "Elevated flat land" .)
I believe the answer is:
plateau
(Other definitions for plateau that I've seen before include "Level outcrop of land" , "Elevated flatland" , "tray that is ornamented" , "Flat-topped height" , "Elevated flat land" .)