  The rotational spectrum of the most stable conformer of ethylene glycol
(HO(CH$_2$)$_2$OH) has been recorded between 360-890 GHz using a
frequency-modulation sub-millimeter spectrometer. The refinement and extension
of the spectroscopic parameters over previous efforts provides 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 6334I in ALMA Band 10
observations. The need for accurate rotational spectra at sub-millimeter
wavelengths/THz frequencies is discussed.
