I've always been interested in this common theme of fort names seen in Morrowind mainly, but with a few occurrences outside of the province as well - most notable is the absence of any such names in Cyrodiil (it only occurs in outpost forts?).

The ones I remember seeing off the top of my head are:

Firemoth - MorrowindFrostmoth - SolstheimBuckmoth - MorrowindMoonmoth - MorrowindBuckmoth - MorrowindHawkmoth - MorrowindSphinxmoth - ElsweyrStormmoth - Black Marsh

So does anyone know what the suffix '-moth' signifies in a name? I know we got all the mystical Moth Priests and such from the Empire, but I don't see any connection between that and the Imperial Outpost Forts. I did some searching for alternate meanings to "moth" and didn't turn anything up; the word is possibly derived from a root simply meaning maggot. That definition doesn't seem to fit with the forts so I'm wondering if anyone else has any stabs at what it could mean?

In the end, I'm satisfied by just saying that it sounded cool and so they used it, but I like attempting to explain things as well and I'm stumped at doing so for this.

Even chest-beating Colovian war leaders take the Niben Heartland seriously in some small way.

Perhaps those forts labeled "-moth" are so denoted because they house an Imperial chapel? I know pretty much every fort in Morrowind had an outpost for the Imperial Cult. You wouldn't need that in Cyrodiil.

It also might be something that Tiber Septim called for as he expanded. He had something to do with the Moth Priests, IIRC. Forts within Cyrodiil are probably older than he is, built during the Interregnum (complete guess, but I don't think there's any other explanation for their existence or their collapsing state in the heart of the empire). Those outside were probably built at his instigation, except in those territories like Skyrim where central authority has long held sway even with the absence of an emperor (explaining why the old forts in Skyrim don't follow this naming convention).

Cyrodiil's culture (pre-Oblivion anyways) revolved around moths as a symbol.

Cult of the Ancestor Moth and all that [censored].

There's no good answer, but I beieve it could be that the legion that is charged to protect Morrowind is the 'Moth Legion'. Then other Legions would have other animals attributed to them, possibly the same animals that appear in Nordic tombs, given the strong ties between Nords and Colovians.

But is the Imperial Cult based on the same doctrines as the Ancestor Moth cult? It's bad, but I haven't read up on those mothballs in a while, though I'm pretty sure they're mainly tasked with lore-keeping and holding the elder scrolls.

Another option is that the legions have nicknames based on moths which actually exist in Tamriel. The Hawk Moth actually exists on our own world for instance. And maybe there are other types of moths which some legions take as mascots: the Buckmoth Legion whose sigil is the hoary buck moth. Just shooting around here.

Edit: I missed this comment. I like that idea about the Moth Legion though, combined with my comment above.

It's the same with Ruhn, lots of Dunmer settlements (or former Dunmer settlements) in Morrowind have Ruhn in the name, off the top of my head I can think of Ald-Ruhn, Tel-Aruhn and Kogoruhn. However i'm not sure of the significance of moth or Ruhn.

EDIT: Just found some dialogue from the quest "Skull-Crusher" from the Imperial Cult that Ruhn translates as 'home' or 'hearth-hall'