The Proto-Indo-European word *welg / wolg
Word *welg / wolg
Transliteration welg
Meaning moisture, wet, liquid food
See also Old Norse: vøkr ‘wet, moist’
Ancient Macedonian: Ὄλγανος ‘river name, deity name’
Synonyms *wed, *h₁res-~h₁ers-, *welk-~welg-, *wegʷ-, *lehat-, *rṓs

OCS vlaga 'moisture', Balto-Slavic *wolʔgaʔ, OHG wolchan n. 'cloud', OHG welc 'moist, mild, withered', ON vøkr 'wet, moist'

Other words that might be of interest
*au̯(e)-9, au̯ed-, au̯er- ‘to flow, to wet water’, *gʷheid- ‘drop’, *mori-/mari- ‘body of water, lake’, *warsa- ‘rainfall, precipitation’, *ab- ‘water, river’, *h₂ekʷ- ‘water’, *h₂ep- ‘water’, *h₂eĝʰero- ‘lake’, *laku- ‘pond’, *lat- ‘swamp’, *ters- ‘dry’, *yeg- ‘ice’, *wódr̥/wudr̥ ‘water’, *s(t)r-ew-/s(t)r-ow-/s(t)r-u-/sreu̯- ‘to flow’, *dehanu- ‘river’, *del- ‘to flow’, *gʷel(s)- ‘to flow, to well up’, *h₁eihₓ(s)- ‘ice’, *h₁wers- ‘rain’, *h₁wes- ‘moist’, *h₂eb(h)- ‘river’, *h₃eust(y)o- ‘estuary, river mouth’, *hₐeghlu~hₐeĝhlu ‘rain’, *hₐehₓperos(?) ‘river bank, shore of sea’, *hₐekʷehₐ- ‘water’, *hₐel- ‘to well up, to flow’, *hₓihₓlu ‘mud, swamp’, *we/ohₓr ‘water’, *yuhₓ-r- ‘water’, *kr̥snehₐ ‘spring, wave’, *kseros- ‘dry’, *leg- ‘drip, trickle’, *lokús ‘water, lake, pond’, *m(e)hₐd- ‘moist, become wet, fat’, *móri ‘sea’, *pen- ‘water’, *srīges- ‘cold, frost’, *stag- ‘drip, seep’, *suhₓ- ‘rain’, *drewentih₂- ‘river name’, *n̥bʰ(ro/ri)- ‘rain’, *siskus ‘dry’