Okay... What exactly is "Dawn Magic"? I've seen it bandied about by the Thalmor in literature concerning them.

Also, presuming that it's magic whose nature was known first in the Dawn eras... would the Thu'um be considered "Dawn Magic", considering their relation to the Dragons?

"Dawn Magic" could be interpreted to mean magic which was known first in the Dawn Era... or it could relate to forms/techniques/understandings of magic which, in their application, affect reality in a fashion akin to the instability of the Dawn Era, such as supreme manipulation of space-time, the bending/nullification (however temporary) of the Earthbones.. temporarly removing Lorkhan's sundered corpse from the sky only to bring it back... or it could just be a BS term haughty altmer use as handwaving.

Edit: I would hesitate to apply the label of "Dawn Magic" to the Thu'um, however. While it might have been practiced pre-convention, it just doesn't seem quite right to call it such. Dawn Magic has merrish conotations.

Unless new information emerges, Imma' go with Thalmor techno-cultural posturing.

The missing magical school of mysticism.

I'm sure Dawn Magic's exist, just not so sure the Thalmor have access to them. The Aylieds were said to have preserved ancient Dawn Magics before their fall.

Dawn magic to me seems to be incredibly powerful magic that can do things that were otherwise only possible during the Dawn era. Basically incredibly powerful world changing magic.