PHRASAL VERB-ERG （使）有一定减少;（使）有一定降低 If something ratchets down or is ratcheted down, it decreases by a fixed amount or degree, and seems unlikely to increase again. （使）有一定减少;（使）有一定降低 [mainly journalism] [Also VERB n PREPOSITION]
We're trying to ratchet down the administrative costs. [VERBPREP. noun]