  Single crystals of Nd$_2$O$_3$ were grown and characterized using neutron
scattering and thermodynamic measurements. Nd$_2$O$_3$ has long-range
antiferromagnetic order below $T_{\rm N}$ = 0.55 K and specific heat
measurements have demonstrated that a significant amount of the magnetic
entropy is released above $T_{\rm N}$. Inelastic neutron scattering experiments
reveal a magnetic mode(s) with little dispersion peaked at $\approx$ 0.37 meV
that is of greatest intensity below $T_{\rm N}$ but persists above 2$T_{\rm
N}$. This persistence of dynamic correlations is likely related to frustrated
interactions associated with the nearly-ideal stacked triangular lattice
geometry of $J_{\textrm{eff}}$ = 1/2 spins on Nd$^{3+}$ ions. The magnetization
is observed to be strongly anisotropic at all temperatures due to crystal field
effects, with easy-plane anisotropy observed. A non-compensated magnetic
structure is inferred from the temperature-dependence of the magnetization when
a magnetic field of sufficient strength is applied within the basal plane near
$T_{\rm N}$, and the evolution of the long-range order is summarized in a
temperature-field phase diagram.
