X-ray diffraction, electrical resistivity, magnetization, specific heat, and thermoelectric power measurements are presented for single crystals of the new filled skutterudite compound {CeOsAs}, which reveal phenomena that are associated with f - electron - conduction electron hybridization. Valence fluctuations or Kondo behavior dominates the physics down to $T$ $sim$ 135 K. The correlated electron behavior is manifested at low temperatures as a hybridization gap insulating state. The small energy gap $Delta$$_1$/k$_B$ $sim$ 73 K, taken from fits to electrical resistivity data, correlates with the evolution of a weakly magnetic or nonmagnetic ground state, which is evident in the magnetization data below a coherence temperature $T$$_{coh}$ $sim$ 45 K. Additionally, the low temperature electronic specific heat coefficient is small, $gamma$ $sim$ 19 mJ/mol K$^2$. Some results for the nonmagnetic analogue compound {LaOsAs} are also presented for comparison purposes.
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