"Chemistry lab" 是指化学实验课。这个短语来源于英语中 "lab" 的意思是 "实验室"，而 "chemistry" 则是 "化学"的意思。
例句：
I have a chemistry lab next period. (我下一节有一门化学实验课。)
The chemistry lab is located on the third floor of the science building. (化学实验室位于科学楼的三楼。)
The students were conducting experiments in the chemistry lab. (学生们在化学实验室里进行实验。)