교

Teaching, religion

교육 – education
교수 – professor
교사 – teacher
교과 – subject
교과서 – textbook (school)
교무실 – teacher’s office
종교 – religion
기독교 – christianity
천주교 – catholicism
불교 – buddhism

School, revise, field officer

학교 – school
초등학교 – elementary school
모교 – alma mater
등교 – attending school
교문 – school gate
교가 – school song
교정 – the campus
교복 – school uniform
교훈 – motto for school discipline
교장 – principal, head a school

Exchange 

교통 – traffic
교통비 – traffic expenses
교체 – shift, change
교환 – exchange
외교 – diplomacy
외교관 – diplomatist
교대 – shift, rotation
교제 – association, friendship
교차로 – intersection

Compare

비교(하다) – comparison, compare
비교적/비교적으로 – comparatively

Bridge

대교 – a large bridge
한남대교 – han nam bridge
잠실대교 – jam sil bridge
런던대교 – lodon bridge
교포 – korean resident[national] abroad
해외 교포 – overseas koreans
재미교포 – korean residents in america
재일교포 – korean residents in japan