This is the 1369th most frequent Korean word.
서울시장
Mayor of Seoul.
Here, '서울시장' is used to signify the official title or role of the Mayor of Seoul.
서울시장은 서울특별시를 대표하는 직위입니다.
The Mayor of Seoul is the position that represents Seoul Metropolis.
In this sentence, '서울시장' refers to the position for which candidates are running in an election.
내일 서울시장 선거가 열립니다.
The election for the Mayor of Seoul will take place tomorrow.
Here, '서울시장' is used to denote the individual currently holding the position of the Mayor of Seoul.