decreasede- 向下、除去+crease 生長、增加→向下生長展開收合de-字首向下、除去crease字根生長、增加字面：向下生長生長的方向往下，即變少、下降。動詞KK [dɪˋkris] /dɪˈkɹis/發音1減少、下降、降低The number of visitors decreased sharply after the storm.暴風雨過後，遊客人數大幅減少。2減少、調降、縮減The clinic decreased his dosage to two pills a day.診所把他的劑量調降到一天兩顆。名詞KK [ˋdiˏkris] /ˈdiˌkɹis/發音1減少、下降、降低There has been a steady decrease in traffic accidents this year.今年交通事故持續下降。2減少量、降幅The report showed a decrease of twelve percent in sales.報告顯示銷售額的降幅為百分之十二。