plateau

1. N-COUNT A plateau is a large area of high and fairly flat land. 高原

A broad valley opened up leading to a high, flat plateau of cultivated land. 一个宽阔的山谷展开，通向一片平坦的高原耕地。

2. N-COUNT If you say that an activity or process has reached a plateau, you mean that it has reached a stage where there is no further change or development. (不再有变化或进展的) 稳定阶段

The U.S. heroin market now appears to have reached a plateau. 美国的海洛因市场目前似乎已进入了一个稳定阶段。