definition of a plateau
plateau noun [C]. âº earth science a âlarge, âflat âarea of âland that is âhigher than the âland around it âº A plateau is also a âperiod during which there are no âbig âchanges: The âcrime ârate in the âcity âreached a plateau in the 1980s and then âdeclined. us /plaeËtoÊ/. plÃ¦ËtoÊ