Unwanted sound that is annoying or interferes with listening. Not all noise needs to be excessively loud to represent an annoyance or interference.<br><br>1) A random energy that contains energy at all audio frequencies. 2) Any unintentional or objectionable signal added to an audio signal.<br><br>In digital imaging, data or unidentifiable marks picked up in the course of scanning or data transfer that do not correspond to the original.Also see chaos.