Just saw this in the newsletter:
I always thought sic was actually an acronym "Spelling/speech in context".
Is there any truth to this understanding?

It's one of those acronyms that are coined after the fact.
Some other examples of spurious acronyms:
news : north, east, west, south
golf : gentlemen only, ladies forbidden
tip : to insure promptness
-Anu Garg

Sic (sic) doesn't have any secret, Latin or something, meaning, then? [disappointment e]