thrum /θrʌm/ ( thrumming, thrummed, thrums )

• 1. 

  V-I When something such as a machine or engine thrums, it makes a low beating sound. (机器、引擎)嗡嗡作响; 发出沉闷声

  例：

  The air-conditioner thrummed.

  空调嗡嗡作响。

• 2. 

  N-COUNT/SOUND Thrum is also a noun. 嗡嗡声

  例：

  ...the thrum of refrigeration motors.

  ...制冷机低沉的嗡嗡声。

  例：

  My head was going thrum thrum thrum.

  我的脑袋嗡嗡嗡地响着。

• 3. 

  V to strum rhythmically but without expression on (a musical instrument) (在乐器上有节奏但无表现力地)随意弹弄