An Etymological Dictionary of Astronomy and Astrophysics

1. An extensive area with a fairly level surface raised sharply above adjacent land.
   

2. A period, phase, or state of little or no growth or decline in something. → Spite plateau.

Etymology (EN): From Fr. plateau, from O.Fr. platel “flat piece of metal, wood, etc.,” diminutive of plat “flat surface or thing,” → plate.

Etymology (PE): Taxtâl, from taxt “flat;” Mid.Pers. taxtag “tablet, plank, (chess)board” + -âl, → -al.