In Korea, there are certain words to address people who are older than you. Words such as “Hyung”, “Unnie”,”” Oppa”, and “Noona” is mostly used to call the people who have close relationship with one, but older. Words like these indicate that no matter how intimate one is to another, they need to respect them because they are older.
In SM Entertainment, they set the rules of addressing a person highly by the standards of grades in school. This is mostly not a problem for those who entered school in just the right age. However, in Korea, you may enter the school a year early when you were born in January or February.
This caused a complicated addressing problem between idols in SM as well.
MinHo of SHINee was born in December of 1991. SuHo of EXO was born in May of 1991. Irene of Red Velvet was born in March of 1991. Considering their birthdays, they should be calling each other names.
However, SuHo went to school a year early, though he was born in May. MinHo used to call him “Hyung” by the rules. Also Irene called SuHo “Oppa”.
But when MinHo debuted, he thought him calling SuHo “Hyung” would give complications to other people, so he asked SuHo whether he could call him by his name. SuHo got mad at MinHo for asking so, and they quarreled about it for a while.
After few arguments, MinHo yield, and continued calling him “Hyung”. However, fans still wonder why Irene has to call him “Oppa” when she is older than him.
Must Read : NCT 127 Talks About SM Entertainment Family Love