a brief, quotable remark, or excerpt from a speech, made as by a politician and suitable for use on TV or radio newscasts: often a dismissive term implying superficiality
See sound bite in American Heritage Dictionary 4
noun
A brief statement, as by a politician, taken from an audiotape or videotape and broadcast especially during a news report: “The box has been spitting forth maddening nine-second sound bites”(Mary McGrory).