It is not Dragonborn, it is Dragonborne, but whatever. I don't think the e really matters.
Borne is to be carried by something.
Its not Dragonborne. There are multiple examples of Dragon Born being used in TES lore. Tiber Septim was described as "dragon born", meaning "of the empire", usually describing a king or emporer, although there are some examples where it was simple describing where someone came from, such as the Nerevarine.
Its Dragon Born.