diminution       
noun [ C or U ]  formal uk/ˌdɪm.ɪˈnjuː.ʃən/ us/ˌdɪm.əˈnuː.ʃən/
 减少;降低
reduction in size or importance
  Regular exercise can result in a general diminution in stress levels. 经常锻炼可以全面缓解精神压力。 
 The company suffered a diminution in profits. 该公司处于利润萎缩的境况。