n. A low sound continued or continuously repeated, as that of a stream running in a stony channel, of a number of persons talking indistinctly in low tones, and the like; a low and confused or indistinct sound; a hum.n. A muttered complaint or protest; the expression of dissatisfaction in a low muttering voice; hence, any expression of complaint or discontent.n. In medicine, any one of various sounds, normal and pathological, heard in auscultation.To make a low continuous noise, like the sound of rushing water or of the wind among trees, or like the hum of bees.To utter words indistinctly; mutter.To grumble; complain; utter complaints in a low, muttering voice; hence, in general, to express complaint or discontent: with at or against.Synonyms To repine, whimper.To utter indistinctly; say in a low indistinct voice; mutter.