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so (Preposition) "under"
10th cent. Old Spanish so. From Latin sub 'id.' From Proto-Italic *supV "below," "upward." From Proto-Indo-European *(h1)u̯po "up." Like sobre, the sudden apparition of *s- from *h1 is inexplicable.
Indo-European
Romance
Portuguese sub, French sous, Aromanian su, Romanian sub
Italic
Oscan συπ (sup) "under," Umbrian su 'id.'
Celtic
Gaulish vo- "under," Old Irish fo 'id.,' Old Welsh guo 'id.,' Old Breton guo 'id.,' Cornish go- 'id.'
Germanic
Gothic uf "under," Old Norse of "over," Old High German oba 'id.'
Hellenic
Ancient Greek ὕπο (hypo) "under"
Indo-Iranian
Sanskrit úpa "toward," Old Avestan upā 'id.'