What is "singleton set" in Chinese? In set theory, a singleton set is a set with just one element.
The term is not in any of my dictionaries, and the only online source I found is one page of zh.wikipedia which just transliterates it as 辛格尔顿.  A search on line shows this is hardly ever used.
A friend who is not a set theorist suggests 单元 for singleton.  I wonder what Chinese set theorists usually use.
单元素集合 is the correct and exact word for singleton set in Chinese, confirmed by a Chinese friend of my who is a mathematician. 

There is a Baidu encyclopaedia entry for 单元素集合, where it is defined as "由唯一一个元素组成的集合", i.e. a set containing a single element, followed by an example {0}.