资料来源 : pyDict

降低电压的,递降的下车,下台,减少

资料来源 : Webster's Revised Unabridged Dictionary (1913)

Step-down \Step"-down`\, a. (Elec.)
   Transforming or converting a current of high potential or
   pressure into one of low pressure; as, a step-down
   transformer.

资料来源 : WordNet®

step-down
     n : the act of decreasing or reducing something [syn: {decrease},
          {diminution}, {reduction}] [ant: {increase}]