rumor

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A piece of unverified information of uncertain origin usually spread by word of mouth.
• noun Unverified information received from another; hearsay.
• transitive verb To spread or tell by rumor.

from The Century Dictionary.

• noun A confused and indistinct noise; a vague sound; a murmur.
• noun Flying or popular report; the common voice.
• noun A current report, with or without foundation; commonly, a story or statement passing from one person to another without any known authority for its truth; a mere report; a piece of idle gossip.
• noun Fame; reported celebrity; reputation.
• noun A voice; a message.
• noun Synonyms and Talk, gossip, hearsay.
• To report; tell or circulate by report; spread abroad.

from the GNU version of the Collaborative International Dictionary of English.

• transitive verb To report by rumor; to tell.
• noun A flying or popular report; the common talk; hence, public fame; notoriety.
• noun A current story passing from one person to another, without any known authority for its truth; -- in this sense often personified.
• noun obsolete A prolonged, indistinct noise.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun countable A statement or claim of questionable accuracy, from no known reliable source, usually spread by word of mouth.
• noun uncountable Information or misinformation of the kind contained in such claims.
• verb transitive To tell a rumor about; to gossip.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb tell or spread rumors
• noun gossip (usually a mixture of truth and untruth) passed around by word of mouth