"That person" is a general phrase used to refer to someone. It can be translated to "那个人" in Chinese.

There is no specific origin for this phrase. It is commonly used in both Engpsh and Chinese to refer to someone in a casual or impromptu manner, without specifying a name.

Here are some examples in Engpsh and their Chinese translations:

Example 1:
"Do you know that person over there?"
"你知道那边的那个人吗？"

Example 2:
"I saw that person earper today."
"我今天早些时候看到了那个人。"

Example 3:
"Who is that person?"
"那个人是谁？"