treble

1. V-T/V-I If something trebles or if you treble it, it becomes three times greater in number or amount than it was. 使增加两倍; 增加两倍[英国英语]

They will have to pay much more when rents treble in January. 房租1月份时将增加两倍，他们得付多得多的钱。

2. PREDET If one thing is treble the size or amount of another thing, it is three times greater in size or amount. 3倍的[英国英语] [正式]

The mine reportedly had an accident rate treble the national average. 据报道，那个矿的事故发生率是全国平均水平的三倍。

3. N-COUNT On a stereo system or radio, the treble is the ability to reproduce the higher musical notes. The treble is also the knob which controls this. (立体声音响或收音机的) 高音; 高音调节旋钮