so- / Indo-European roots
This, that (nominative).For other cases see to-
1. the1 from Late Old English the, masculine demonstrative pronoun, replacing se (with th- from oblique forms; see to-)
2. hoi polloi from Greek ho, the.
3. Feminine form *syā-. she from Old English sēo, sīe, she, from Germanic *sjō.
4. Compound variant form *sei-ke (*-ke"this"; see ko-) sic1 from Latin sīc, thus, so, in that manner.
[Pokorny so(s) 978.]