hum/hʌm; hʌm/ v -mmed, -mming 1 [I,T] to make a tune by making a continuous sound with your lips closed 哼〔曲子〕: If you don't know the words, just hum. 如果不会歌词就哼曲调吧。 2 [I] to make a low continuous sound 发出嗡嗡声，嗡嗡叫: insects humming in the sunshine 在太阳光下嗡嗡叫唱的昆虫 3 be humming if a place is humming, it is very busy and there is a lot of activity 〔地方〕繁忙