Tho

wiktionary

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From Middle English tho, tha, from Old English þāpl(“the, those”), from Proto-Germanic *þai(“those”), from Proto-Indo-European *to-, *só(“that”). Cognate with Saterland Frisian dopl(“the”).

From Middle English tho, tha, from Old English þā(“then, when”), from Proto-Germanic *þa-(“that”), from Proto-Indo-European *to-, *só(“that”). See also German da(“then, thereupon”).

Mostly found in American English; alteration of though. Compare tho'.

etymonline

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tho (conj.)

in modern use, an abbreviated spelling of though.