1. 化学
    Chemistry is the scientific study of the structure of substances and of the way that they react with other substances.

2. (物质的)化学组成，化学成分，化学反应
    The chemistry of an organism or a material is the chemical substances that make it up and the chemical reactions that go on inside it.

chemistry的近义词

    e.g. We have literally altered the chemistry of our planet's atmosphere...
           我们确实改变了地球大气层的化学构成。
    e.g. If the supply of vitamins and minerals in the diet is inadequate, this will result in changes in body chemistry.
           如果饮食中的维生素和矿物质含量太低，将会引起人体化学结构的变化。

3. (互相之间的)吸引，亲密
    If you say that there is chemistry between two people, you mean that is obvious they are attracted to each other or like each other very much.

    e.g. ...the extraordinary chemistry between Ingrid and Bogart...
           英格丽和鲍嘉之间的情意绵绵
    e.g. Janis and I became friends but we were never close. The chemistry wasn't there.
           我和贾妮斯成了朋友，可我们从未走得太近，没有那种感觉。