  We measure the star cluster mass function for the Local Group galaxy M33. We
use the catalog of stellar clusters selected from the Panchromatic Hubble
Andromeda Treasury: Triangulum Extended Region (PHATTER) survey. We analyze 711
clusters in M33 with $\rm 7.0 < log(Age/yr) < 8.5$, and log($M/M_{\odot}$) $>$
3.0 as determined from color-magnitude diagram fits to individual stars. The
M33 cluster mass function is best described by a Schechter function with power
law slope $\alpha = -2.06^{+0.14}_{-0.13}$, and truncation mass
log($M_c/M_{\odot}$) $= 4.24^{+0.16}_{-0.13}$. The data show strong evidence
for a high-mass truncation, thus strongly favoring a Schechter function fit
over a pure power law. M33's truncation mass is consistent with the previously
identified linear trend between $M_c$, and star formation rate surface density,
\SigSFR. We also explore the effect that individual cluster mass uncertainties
have on derived mass function parameters, and find evidence to suggest that
large cluster mass uncertainties have the potential to bias the truncation mass
of fitted mass functions on the one sigma level.
