This is the 7697th most frequent Japanese word.
占領
Occupation; capture or seizure of territory.
The word '占領' is used in a historical context to mean 'occupied' or 'seized militarily'.
その地域は昔、敵軍によって占領された。
That area was occupied by enemy forces long ago.
Here, '占領' is used figuratively to describe 'domination' or 'being filled by' a particular group.
アートギャラリーが若い世代によって占領されているようだ。
The art gallery appears to be dominated by the younger generation.
In this case, '占領' describes an action where one entity is overtaking or replacing another in terms of popularity or presence.