[pla.teau] n, pl plateaus or pla.teaux [F, fr. MF, platter, fr. plat flat] (1796) 1 a: a usu. extensive land area having a relatively level surface raised sharply above adjacent land on at least one side: tableland b: a similar undersea feature
2. a: a region of little or no change in a graphic representation b: a relatively stable level, period, or condition
3: a level of attainment or achievement "the 500-point ~"
[2]plateau vi (1939): to reach a level, period, or condition of stability