  We report non-resonant x-ray Raman scattering (XRS) measurements from
hexagonal boron nitride for transferred momentum from 2 to 9
$\mathrm{\AA}^{-1}$ along directions both in and out of the basal plane. A
symmetry-based argument, together with real-space full multiple scattering
calculations of the projected density of states in the spherical harmonics
basis, reveals that a strong pre-edge feature is a dominantly $Y_{10}$-type
Frenkel exciton with no other \textit{s}-, \textit{p}-, or \textit{d}-
components. This conclusion is supported by a second, independent calculation
of the \textbf{q}-dependent XRS cross-section based on the Bethe-Salpeter
equation.
