n.[U]

1. 效率；效能；功效
   These machines have increased our work efficiency many times.

   這些機器使我們的工作效率提高了許多倍。

2. 【物】效率

n.

1. the state or quality of being efficient.
2. technical the ratio of the useful work performed by a machine or in a process to the total energy expended or heat taken in.