  Multiquark correlations inside hadrons can have a significant and in some
cases even striking impact on the hadron spectrum. We show how such
correlations in general, and mesons with a dominant tetraquark content in
particular, emerge holographically in the AdS/QCD framework. On this basis, we
arrive at a holographic realization of an exceptionally strong four-quark
binding and a correspondingly large tetraquark component in the lightest scalar
mesons. Higher-lying tetraquark excitations, on the other hand, become too
broad to form supernumeral scalar states.
