1. 变换;转换;转变;改变
    Conversion is the act or process of changing something into a different state or form.

conversion

    e.g. ...the conversion of disused rail lines into cycle routes...
           将废弃的铁路线改成自行车道
    e.g. A loft conversion can add considerably to the value of a house.
           将阁楼改造一下就可以使房子的价值大增。

2. (宗教、信仰等的)改变，皈依，归附
    If someone changes their religion or beliefs, you can refer to their conversion to their new religion or beliefs.

    e.g. ...his conversion to Christianity...
           他皈依基督教
    e.g. It's hard to trust the President's conversion.
           总统信仰的改变让人难以相信。

3. (橄榄球运动中的)附加得分
    In rugby, if a player makes or kicks a conversion, he scores points by kicking the ball over the goal after a try has been scored.