epoq [f.] 'dew', plur. 'dewdrops' (ll.). ≈ IE *h,uers- 'rain'… DER epaεlς, t εraε εlς 'dewy' (ll., AP)
This passage identifies the PIE root *h₁uers- ('rain, dew') as the etymological origin of Greek ἕρση, directly establishing 'Ers' as a reconstructed root with concrete semantic progeny in the archaic Greek lexicon.
, Etymological Dictionary of Greek, 2010thesis