I have been struggling with this and hope someone can give me the
proper guidance....
The Norse Vanic aquatic deity Njord is supposed to be linguistically
related to Nerthus (via the Proto-Gmc Nerthuz).
If we can connect Nerthuz with Nereus we might then assume a rather
precise match between Njord & Nereus.
C. Gwinn stated:
"There likely is a connection between Nereus and the Irish Nera (who
seems to be a late reflection of the Gaulish god Nerios, the tutelary
divinity of the healing waters at Neris-les-Bains, France)."
On Nerios a quick search reveals:
Nerius is known from inscriptions found at Haegen, Bas-Rhin, France
where he is invoked along with Bugius as well as at Néris-le-Bains,
Allier, France.
At Néris-le-Bains the tale of the town itself is inextricably linked
with its thermal springs, which in early Celtic times seem to have
been linked with the deity Nerios.
Eventually a township arose at the
crossroads between two main roads and this was given the name
Neriomagos (Nerios' Marketplace) .
As to Nera:
Nera is a warrior in the Ulster Cycle, there are some aquatic
references present in the tale as well as a trip to the Underworld.
There are also Nera Rivers which are tributaries of the Tiber, the
Indigirka, and the Danube.
Lastly Aigius mentioned the "Lithuanian word NERE, meaning WAS DIVING"
In light of this evidence does it seem valid to suggest that all are
derived from *Ner(1)- , meaning "under"?
Many thanks!
-Aydan