Hum

Hum is a verb which refers to either:

A sound with a particular tambor, usually a monotone or with slightly varying tones, often produced by machinery in operation or by insects in flight, or
An action whereby a human vocally produces such a sound, but usually with musically varying tonality.

The action of humming is produced simply by producing a wordless tone, such as in scat singing (a wordless form of singing), but with the mouth completely closed so that the sound emerges from the nose. This necessarily keeps the volume at a low level, so humming is often not useful in musical productions, but is nonetheless sometimes used.

Often, people hum either individually or when in group singing when they don't know the words.

Frank Zappa used hum as a pun in his song, Dynamo Hum, with the reference being both to the hum made by a generator (dynamo) in operation, and to the humming action of a woman giving fellatio.

Hum, like Zahumlje, is a historic name for areas of today's Herzegovina.

Hum, locality in central Istria, near Roč in Istria county (Croatia), considered to be the smallest town in the world with just 22 residents.