This is the 349th most frequent Korean word.
공동
"Joint" or "shared."
In this context, '공동' (gongdong) refers to something done together or jointly.
공동으로 프로젝트를 진행하며 협력했다.
We collaborated and worked on the project jointly.
Here, '공동' (gongdong) is used to describe something shared among residents, such as a communal area.
이 아파트는 공동 구역이 넓어서 편리하다.
This apartment has a spacious communal area, which is convenient.
In this sentence, '공동' (gongdong) implies something common or shared, in this case, shared interests among individuals.