Archaic second person singular pronoun meaning 'you' when addressing one person informally or intimately. Still used in poetry, prayer, and some dialects.
From Old English 'þu' (thou), cognate with German 'du' and Latin 'tu'. Part of the original Germanic pronoun system that distinguished between formal/plural 'you' and informal/singular 'thou'. Gradually replaced by 'you' in most contexts by the 17th century.
The loss of 'thou' from everyday English eliminated a crucial social distinction that most other European languages maintain - the difference between formal and intimate address. Ironically, this 'informal' pronoun now sounds incredibly formal to modern ears because we mainly encounter it in religious texts and Shakespeare.
Complete word intelligence in one call. Free tier — 50 lookups/day.