What is a 흰자위?

ANSWER: It depends. If you are talking about an egg, it is the white inner part of the egg, but if you are talking about an eye, it is the white part of the eye. The 흰 part of the word means "white," but I am not exactly sure what the 자위 part of the word means except that it seems to mean either "color" or "part" when referring to eggs or eyes. In North Korea, 자위 is also used to refer to the color of fruit when it starts to ripen, so maybe at one time in the past 자위 meant "color" since it requires a color adjective in front of it for it to have any real meaning today.

In Korea, the white part of an egg is called 흰자위, and the yellow part, or yolk, is called 노른자위. Both 노랗다 and 노르다 mean "yellow," but when talking about the yolk of an egg, you should say 노른자위, not 노란자위. 

When you are talking about the white part of an eye (눈), you should probably say 눈의 흰자위 so that people won't think you are talking about the white part of an egg. Likewise, you could say 달걀의 흰자위 to clarify that you are talking about an egg (달걀), not an eye (눈).

Finally, what does 검은자위 mean? The word 검다 means either "black" or "dark," but when Koreans say 검은자위, they are referring to the colored "iris" of the eye, not to the black "pupil" of the eye. So, the better literal translation of 검은자위 would be "the dark part of the eye" rather than "the black part of the eye," especially since Korean eyes tend to be dark brown, making it harder to distinguish the colored "iris" of the eye from the black "pupil." For the black pupil of the eye, Koreans use the word 눈동자. By the way, 가맣다 or 까맣다 also means either "black" or "dark," but when talking about the colored iris of the eye, you should say 검은자위, not 까만자위.

By the way, instead of 흰자위, 노른자위, and 검은자위, some Koreans say 흰자, 노른자, and 검은자.