murmur

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. A low, indistinct, continuous sound: spoke in a murmur; the murmur of the waves.
2. n. An indistinct, whispered, or confidential complaint; a mutter.
3. n. Medicine An abnormal sound, usually emanating from the heart, that sometimes indicates a diseased condition.
4. v. To make a low, continuous, indistinct sound or succession of sounds.
5. v. To complain in low mumbling tones; grumble.
6. v. To say in a low indistinct voice; utter indistinctly: murmured his approval.

Century Dictionary and Cyclopedia

1. 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.
2. n. A muttered complaint or protest; the expression of dissatisfaction in a low muttering voice; hence, any expression of complaint or discontent.
3. n. In medicine, any one of various sounds, normal and pathological, heard in auscultation.
4. To make a low continuous noise, like the sound of rushing water or of the wind among trees, or like the hum of bees.
5. To utter words indistinctly; mutter.
6. To grumble; complain; utter complaints in a low, muttering voice; hence, in general, to express complaint or discontent: with at or against.
7. Synonyms To repine, whimper.
8. To utter indistinctly; say in a low indistinct voice; mutter.

Wiktionary

1. n. countable Low or indistinct sounds or speech.
2. n. medicine The sound made by any condition which produces noisy, or turbulent, flow of blood through the heart.
3. n. A muttered complaint or protest; the expression of dissatisfaction in a low muttering voice; any expression of complaint or discontent

GNU Webster's 1913

1. n. A low, confused, and indistinct sound, like that of running water.
2. n. A complaint half suppressed, or uttered in a low, muttering voice.
3. v. To make a low continued noise, like the hum of bees, a stream of water, distant waves, or the wind in a forest.
4. v. To utter complaints in a low, half-articulated voice; to feel or express dissatisfaction or discontent; to grumble; -- often with at or against.
5. v. To utter or give forth in low or indistinct words or sounds.

WordNet 3.0

1. v. make complaining remarks or noises under one's breath
2. n. a schwa that is incidental to the pronunciation of a consonant
3. n. an abnormal sound of the heart; sometimes a sign of abnormal function of the heart valves
4. v. speak softly or indistinctly
5. n. a complaint uttered in a low and indistinct tone
6. n. a low continuous indistinct sound; often accompanied by movement of the lips without the production of articulate speech