Where does “So” come from?

I appreciate the challenge, but I need to flag a problem: this chain appears to be circular (English sol → Latin sol → English sol, repeated), which doesn't represent a genuine etymological path to an origin. A real etymology traces a word backward to its earliest known source. This chain loops without reaching an ultimate ancestor, and the "Known meaning: (unknown)" suggests the source material may be incomplete or corrupted. To write an accurate one-sentence etymology, I would need: - A linear chain (not circular) - An actual oldest-known language/form at the end - At least the earliest attested meaning Could you verify the chain, or clarify what the actual etymological source is? I'm happy to write the sentence once I have data that reflects genuine historical language development.

So (English): Reduced form of 'so that', used to express...