We can use 외할아버지 to refer to a maternal grandfather.
Here 외 comes from hanja 外, meaning "outside". It is the same 외 that is used in 외국어 (foreign language), for example.
What is the logic behind using "outside" for the maternal side?
2 Answers
As with many other Confucianism-influenced countries, the Korean society was under patriarchy, male dominance. The family structure was patrilineal as well. When a woman got married, it was said that she became a member of her husband’s family; it was she that entered the family from the outside. And children got their fathers’ surnames. Hence the “친(親)-” (“close”) prefix for paternal terms, and the “외(外)-” (“external”) prefix for maternal terms.
Images from Analogue: A Hate Story, a visual novel based on the Chosun dynasty. Historically accurate as for the structure of genealogy records back then.
1) Have you ever been to 외가 (=외갓댁=house of father of mother) ?
외가에 가 봤었니 ?
@외 = outside, 가 = house
2) 외가 has contrary word 친가.
So father of father is 친 할아버지 or 할아버지.
Older brother of father of father is called 큰할아버지. And we can say "Have you ever been to a house of older brother of grandfather (=큰할아버지댁) ? Physically, 큰할아버지댁 needs the word "외" as like "외갓댁". But we do not use.
3) Child follows father's family name (Even though recently rule is changed, but the trend still prevails, in my thought).
Traditionally, in Korea, when a girl married, then she is not a member of our family and is subordinate to other. At here, there are several reasons. (Important roles in family are accomplished by men)
a) The unbroken line for family is important. Surely, member in the line is a man.
b) Woman can not have a job.
