hum

Definitions

• A hummed tune, i.e. created orally with lips closed.
• An often indistinct sound resembling human humming.
• Busy activity, like the buzz of a beehive.
• (UK) unpleasant odour.
• (dated) An imposition or hoax; humbug.
• (obsolete) A kind of strong drink.
• A phenomenon, or collection of phenomena, involving widespread reports of a persistent and invasive low-frequency humming, rumbling, or droning noise not audible to all people.