You may know the English letters A, B and C. But do you know there are people called ABCs? Do you know there is such a thing as "a banana person"? How strange! ABC means American-born Chinese. An ABC is a Chinese, but was born in the United States. Sometimes, people call an ABC a "banana person". A banana is yellow outside. So, when a person is a "banana", he or she is white inside—thinking like a Westerner and yellow outside—looking like a Chinese.
Usually, ABCs know little about China or the Chinese language. Some of them don't speak Chinese. But if ABCs cannot speak Chinese, can we still call them Chinese people? Yes, of course. They are overseas (海外的) Chinese. These people may be citizens (公民) of another country like the US, Canada or Singapore. But they have Chinese blood. Their parents, grandparents or even great-grandparents were from China. They all have black eyes and black hair. But they are not Chinese citizens. They are people of the People's Republic of China. For example, we all know the famous scientist C. N. Yang (杨振宁). He got the Nobel Prize for Physics in 1957. Chinese people love him. But he is an American citizen.