Source : Webster's Revised Unabridged Dictionary (1913)

You \You\ ([=u]), pron. [Possess. {Your} ([=u]r) or {Yours}
   ([=u]rz); dat. & obj. {You}.] [OE. you, eou, eow, dat. &
   acc., AS. e['o]w, used as dat. & acc. of ge, g[=e], ye; akin
   to OFries. iu, io, D. u, G. euch, OHG. iu, dat., iuwih, acc.,
   Icel. y[eth]r, dat. & acc., Goth. izwis; of uncertain origin.
   [root]189. Cf. {Your}.]
   The pronoun of the second person, in the nominative, dative,
   and objective case, indicating the person or persons
   addressed. See the Note under {Ye}.

         Ye go to Canterbury; God you speed.      --Chaucer.

         Good sir, I do in friendship counsel you To leave this
         place.                                   --Shak.

         In vain you tell your parting lover You wish fair winds
         may waft him over.                       --Prior.

   Note: Though you is properly a plural, it is in all ordinary
         discourse used also in addressing a single person, yet
         properly always with a plural verb. ``Are you he that
         hangs the verses on the trees, wherein Rosalind is so
         admired ?'' --Shak. You and your are sometimes used
         indefinitely, like we, they, one, to express persons
         not specified. ``The looks at a distance like a
         new-plowed land; but as you come near it, you see
         nothing but a long heap of heavy, disjointed clods.''
         --Addison. ``Your medalist and critic are much nearer
         related than the world imagine.'' --Addison. ``It is
         always pleasant to be forced to do what you wish to do,
         but what, until pressed, you dare not attempt.''
         --Hook. You is often used reflexively for yourself of
         yourselves. ``Your highness shall repose you at the
         tower.'' --Shak.

Yours \Yours\ (["u]rz), pron.
   See the Note under {Your}.

Thou \Thou\, pron. [Sing.: nom. {Thou}; poss. {Thy}or {Thine};
   obj. {Thee}. Pl.: nom. {You}; poss. {Your}or {Yours}; obj.
   {You}.] [OE. thou, [thorn]u, AS. [eth][=u], [eth]u; akin to
   OS. & OFries. thu, G., Dan. & Sw. du, Icel. [thorn][=u],
   Goth. [thorn]u, Russ. tui, Ir. & Gael. tu, W. ti, L. tu, Gr.
   sy`, Dor. ty`, Skr. tvam. [root]185. Cf. {Thee}, {Thine}, {Te
   Deum}.]
   The second personal pronoun, in the singular number, denoting
   the person addressed; thyself; the pronoun which is used in
   addressing persons in the solemn or poetical style.

         Art thou he that should come?            --Matt. xi. 3.

   Note: ``In Old English, generally, thou is the language of a
         lord to a servant, of an equal to an equal, and
         expresses also companionship, love, permission,
         defiance, scorn, threatening: whilst ye is the language
         of a servant to a lord, and of compliment, and further
         expresses honor, submission, or entreaty.'' --Skeat.

   Note: Thou is now sometimes used by the Friends, or Quakers,
         in familiar discourse, though most of them corruptly
         say thee instead of thou.