thrum
Word family nounthrummerthrummingadverbthrumminglyadjectivethrummyverbthrum
thrum /θrʌm/ verb (thrummed, thrumming) [intransitiveI] CSSOUNDto make a low sound like the sound of an engine 发低沉的嗡嗡声 The engine thrummed into life. 引擎轰轰地发动了起来。
—thrum noun [singular] the thrum of passing cars 来往车辆的轰轰声
Origin thrum (1500-1600) From the sound