  The superconducting order parameter in the iron-chalcogenide superconductor
FeTe$_{0.55}$Se$_{0.45}$ ($T_\textrm{c}$ = 14.2 K) is investigated by
point-contact Andreev reflection spectroscopy. The energy gap magnitude (3.8
meV at 1.70 K) and temperature dependence as extracted from the Andreev
conductance spectra reveal strong-coupling superconductivity and is consistent
with $s$-wave order parameter symmetry. No clear evidence for multiple order
parameters or interference from multiple bands is observed. A conductance
enhancement persists above $T_\textrm{c}$ to $\sim 18-20$ K and possible
origins, including novel quasiparticle scattering due to strong
antiferromagnetic spin fluctuations, are discussed.
