pronoun[second person singular]
Old English thu, of Germanic origin; related to German du, from an Indo-European root shared by Latin tu
In modern English, the personal pronoun you (together with the possessives your and yours) covers a number of uses: it is both singular and plural, both objective and subjective, and both formal and familiar. This has not always been the case. In Old English and Middle English some of these different functions of you were supplied by different words. Thus, thou was at one time the singular subjective case (thou art a beast), while thee was the singular objective case (he cares not for thee). In addition, the form thy (modern equivalent your) was the singular possessive determiner and thine (modern equivalent yours) the singular possessive pronoun, both corresponding to thee. The forms you and ye, on the other hand, were at one time reserved for plural uses. By the 19th century these forms were universal in standard English for both singular and plural, polite and familiar. In present-day use thou, thee, thy, and thine survive in some traditional dialects but otherwise are found only in archaic contexts.