Today I've learned the word 회의, which means "Meeting" I have noticed quite a few Korean people have a misunderstanding of this word. So despite saying "I am meeting my friend today" (오늘은 친구를 마나요), when one says "I have a meeting today" it refers to something official, as a business meeting. you can say "I am meeting up with a friend" or "I am meeting a friend" which will refer to a friendly situation. On that note, the same goes for the word "appointment", which will refer to either going to the doctor or some kind of a more official meeting, which usually involved booking it ahead of time and it being part of a specific schedule.