This is the 15374th most frequent Korean word.
벌스데이
"Birthday" (loanword from English).
벌스데이 is used to refer to a birthday in a casual and borrowed form, derived from English 'birthday'.
오늘은 벌스데이 축하파티에 갈 거예요.
Today, I am going to the birthday celebration party.
벌스데이 is being referenced as someone's own birthday in a personal context.
그는 자신의 벌스데이를 특별하게 보내고 싶어했어요.
He wanted to spend his birthday in a special way.
벌스데이 here is used to signify an occasion of celebration for a friend's birthday.