The rotational spectrum of the most stable conformer of ethylene glycol (HO(CH2)(2)OH) has been recorded between 360-890 GHz using a frequency-modulation submillimeter spectrometer. The refinement and extension of the spectroscopic parameters over previous efforts provide predicted catalog frequencies for ethylene glycol with sufficient accuracy for comparison to high-frequency astronomical data. The improvement in the cataloged line positions, and the need for improved accuracy enabled by high-frequency laboratory work, is demonstrated by an analysis of ethylene glycol emission at 890 GHz in the high-mass star-forming region NGC 63341 in ALMA Band 10 observations. The need for accurate rotational spectra at submillimeter wavelengths/THz frequencies is discussed.