Board Thread:Lore Discussion/@comment-23371555-20140725140907/@comment-29845234-20161003114150

Also note that oversoul is only used in a few specific contexts, where the split between the larger and smaller entities isn't overly clear. There are only 2 examples that I've heard about:

The AKA oversoul - the constituent parts of the time god, Auri-El, Akatosh, Alduin and so on. Exactly which of these is the "true" time god is unclear.

The Talos oversoul - Zuin, Hjalti and Wulfharth. All of these go in to making up Talos, although Hjalti is most commonly identifed with Tiber Septim.

Each of these has a whole and distinct parts, which isn't something that is common in TES at all. I've not heard of the "Lorkhan oversoul" for exampl,e despite Lorkhan having multiple aspects (Shor, Shezzar etc). The same goes for other gods with different aspects (Zenithar/Z'en, Arkey/Orkey, Kynareth/Kyne etc). Whether this is simple convention in the fandom or there is an actual difference here I don't know.

However, the above two examples have had very specific things done to them at various points in Tamriel's history - Aka by the Selectives dancing on the tower to split the Merish elements away from Auriel, in the process creating Akatosh, and Talos being (probaby) created by the Hjalti-Zurin-Wulfharth enantiomorph. The other examples don't have that meddling, just different cultural interpretations. I would therefore think that the therm "oversoul" only really applies when there has been some definite metaphysical upheaval going on, and then it only really seems to apply to the Aedra (I've not heard the term applied to Sheo/Jyggylagg, for example).