orbit

1. N-COUNT An orbit is the curved path in space that is followed by an object going around and around a planet, moon, or star. (天体运行的) 轨道[also 'in/into' N]

Mars and Earth have orbits which change with time. 火星和地球的轨道随着时间而发生改变。

2. V-T If something such as a satellite orbits a planet, moon, or sun, it moves around it in a continuous, curving path. 环绕…的轨道运行

In 1957 the Soviet Union launched the first satellite to orbit the earth. 1957年，苏联发射了第一颗环绕地球运行的人造卫星。