(1):
(n.) A low, continued moan; a murmur.
(2):
(v. t.) To soothe by singing softly.
(3):
(n.) A low singing; a plain, artless melody.
(4):
(v. t.) To sing in a low tone, as if to one's self; to hum.
(5):
(v. i.) To hum or sing in a low tone; to murmur softly.
(6):
(v. i.) To make a continuous hollow moan, as cattle do when in pain.