equilibrium
/ˌi:kwɪˈlɪbrɪəm, alsoˌek-; ˌikwə`lɪbrɪəm, ɛk-/ n[U]
1 state of being balanced 平衡; 均势
This pair of scales is not in equilibrium. 这个天平不平衡.
He can't maintain enough equilibrium to ride a bike. 他骑自行车不能保持平衡.
2 (fig 比喻) balanced state of mind, feelings, etc （心情、 感情等）平静
She lost her usual equilibrium and shouted at him angrily. 她一反常态, 向他愤怒地叫喊.