교원이 · 교원을
teacher (official term), teaching staff
Example
정부는 내년에 교원 수를 늘리기로 했습니다.
The government decided to increase the number of teachers next year.
Word parts
교 teach+원 member
Literally 'teaching member'.
Good to know
교원 is an official, legal term; in everyday speech people say 선생님 or 교사.