prep. on, upon; at, down upon

Ahrk fin zul, rok drey kod, nau tol morokei frod, rul lot Taazokaan motaad voth kein!
And the Voice, he did wield, on that glorious field, when great Tamriel shuddered with war!
(Book, Songs of Skyrim)

The freedom of the sky beckons! Yet I stay here, nau gol, as promised.
Nau gol = “on earth” = “grounded”
(Odahviing, 0004DE42)

Kendov krif ok kosiil Vokul, nuz jun Gaar niin nau ok hokoron.
The warrior fights his inner evils, but the king unleashes them on his enemies.
(Word Wall for Gaar, Cyclone)

Means ‘on top of’ or ‘down upon’. Does not mean ‘active’ as in ‘to turn on’. Not used in reference to time as in ‘on time’ or ‘on this day’. Not used to indicate condition, as in ‘on cue’ or ‘on demand’.