侦探小说用英文怎么说？是“detective story ”吗？

可以用：detective novel
引用萨缪尔·贝克特的作品介绍：
Molloy, for instance, still retains many of the characteristics of a conventional novel—time, place, movement and plot—and is indeed, on one level, a detective novel.

也可以用：detective story
引用英文网站detective-story：
The detective story soon expanded to novel length.

我个人认为用第一个比较好。

侦探小说 [简明汉英词典]
whodunit

detective fiction

是啊,就是这个啦!

恩

是