  We performed thermoelectric Hall conductivity $\alpha_{xy}$ measurements on
single-crystal graphite in the quantum limit up to 13 T. Both electrical and
thermoelectric transport measurements were performed on the same crystal to
extract pure $\alpha_{xy}$, avoiding any sample quality dependence. The
$\alpha_{xy}$ converges to a plateau in the quantum limit with a linear
dependence on temperature. This behavior is analogous to the quantized
thermoelectric Hall effect (QTHE) observed in three-dimensional Dirac/Weyl
nodal-point semimetals, and experimentally confirms a theoretical proposal on
the QTHE in semimetals with nodal lines as in graphite.
