Thou is a way to say you in an older style of English or poetic writing.(pronoun)
An example of thou is the wording of the biblical Ten Commandments, “Thou shalt not…”.
See thou in Webster's New World College Dictionary
Origin: ME < OE thu, akin to Ger du < IE *tu > L & Sans tu
See thou in American Heritage Dictionary 4
Origin: Middle English
Origin: , from Old English thū, second person nominative sing. personal pron.; see tu- in Indo-European roots.
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