This is the 180th most frequent Korean word.
에서
"에서" is a Korean particle meaning "at," "in," or "from," indicating location or starting point.
에서 is used here to indicate the location where the event (enjoying the festival) takes place.
서울에서 많은 사람들이 축제를 즐깁니다.
In Seoul, many people enjoy the festival.
에서 is used to specify the location (library) where the activity (studying) occurs.
도서관에서 공부하는 것은 집중에 도움이 됩니다.
Studying in the library helps with concentration.
에서 indicates the place (school) where the action (meeting friends) happens.