What is the difference between 中国人, 華人, 漢人, and 唐人?

Question

I looked at the dictionary definitions of 中国人, 華人, 漢人, and 唐人, and it appears that all of them mean "Chinese person".

Questions:

1. What is the difference between them?
2. Why are there so many ways of saying "Chinese person"?
3. What is the most common way of referring to a Chinese person (including persons of Chinese ancestry, not just from China)?

Answer 1

It's like this:

1. 中国人: "a person with Chinese nationality"
2. 漢人:
   1. "a person from the Han dynasty"
   2. "a person of Han (Chinese) ethnicity"
3. 華人: "a person of ethnically Han ancestry living outside of China"
4. 唐人:
   1. "a person from the Tang dynasty"
   2. "a Seric; a Cathayan"

The word 中国人 (#1) is by far the most common word corresponds to English Chinese, that is what most lay people naively imagine about the word (which technically tends to be #2-2).

About #2-1 and #4-1, I don't explain here because they are obviously historical terms.

For #2-2, it's good to know that both PRC and Taiwan are multiethnic countries, just >90% of whose population is made up by people who identify themselves as 漢族 "Han ethnicity", or Chinese in a narrow sense. But as you may suspect, this is merely an academic term in Japan that only experts would know.

On top of this, #3 is, in short, overseas Chinese (#2-2) people, or Chinese-hyphen-somewhere people (a.k.a. 華僑【かきょう】).

And for #4-2, did you know those English words? They are older names for Chinese, in other words, you aren't going to use it until you write a historical novel in Japanese.

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So, basically what you have to memorize is only 中国人, and for those who have Chinese ancestry but not from China, you should use 華人/華僑 (individual) or 中国系 (group or property). For instance, a Chinese-American is described as 中国系アメリカ人 or 中国系米国人 in Japanese.