Korean Family Titles
매제
maeje · Younger sister's husband
Relationship
my younger sister → her husband
Who uses it
Her older siblings, about her husband.
When you call them
A brother calls him 매제; a sister calls him 제부. Both may use surname + 서방.
When you talk about them
To others, 매제 or 제부.
Example
제부, 우리 동생 잘 부탁해요.Jebu, please take good care of my little sister.
Based on the standard etiquette of the National Institute of Korean Language; families and regions vary.