milestone
noun [ C ] uk/ˈmaɪl.stəʊn/ us/ˈmaɪl.stoʊn/ (UK also milepost)
(STONE/POST)
里程碑，里程标
a stone or post at the side of the road that shows the distance to various places, especially to the nearest large town
(IMPORTANT EVENT)
里程碑；重大事件；转折点
an important event in the development or history of something or in someone's life
He felt that moving out of his parents' home was a real milestone in his life. 他感到搬出父母家是他一生中一个真正的转折点。