<p><strong>Noun</strong></p><ul><li>a low or subdued tone; to speak in undertones</li><li>an unobtrusive or background sound; an undertone of static from the receiver</li><li>an underlying quality or element; undercurrent (e.g., there was an undertone of regret in his refusal)</li><li>a subdued color; a color modified by an underlying color</li></ul>