친구friend 구old; former 구세대old generation 구간old edition 구관former official 구관old building 구교Catholicism 구면acquaintance 구법old law 구습old customs; old-fashioned practices

금강석diamond 보석jewel 비석tombstone; monument 석류pomegranate tree 석유oil; petroleum 일석이조killing two birds with one stone 초석cornerstone; foundation stone 치석tartar; scale; plaque 타산지석learning from someone else's mistakes; lesson from someone else's failures 탄생석birthstone

악기musical instrument 체온기thermometer 충전기battery charger 가습기humidifier 감지기sensor 공기bowl 기구utensil; tool; implement 녹음기recorder 도자기pottery 무기weapon; arms