급감rapid decrease; sharp fall; nosedive 급증rapid increase 급행열차express train 긴급emergency 긴급회의emergency meeting 응급실ER; emergency room 초특급being very speedy 특급special express 화급urgency; emergency 구급relief; rescue

개선triumpant return 개선문triumphal arch 나선spiral; helix 나선형helical form; spiral; helix 선율melody; tune 선풍sensation 선풍적being sensational 선풍적sensational 선회wheel; spinning 알선good offices; recommendation

회hoe 회전문revolving door 횟수number of times; frequency 매회each time 매회every time 우회전right turn 일회용disposable; throwaway 일회용품disposable; throwaway 좌회전turning left 회갑one's sixtieth birthday; the age of sixty