If It's Resonance, What Is Resonating?

The resonance terminology that accompanies use of more than one Lewis-type structure to describe delocalized bonding in molecules has been leading students astray for more than half a century. In this article I review the origin of the terminology and how the original usage has evolved to reduce confusion. I furthermore suggest that substitution of more easily understood terms that lack the gratuitous implications of the word resonance could finally eliminate the confusion.