Source : Webster's Revised Unabridged Dictionary (1913)

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.

Thine \Thine\ ([th][imac]n), pron. & a. [OE. thin, AS.
   [eth][=i]n, originally gen. of [eth]u, [eth][=u], thou; akin
   to G. dein thine, Icel. [thorn]inn, possessive pron.,
   [thorn][=i]n, gen. of [thorn][=u] thou, Goth. [thorn]eins,
   possessive pron., [thorn]eina, gen. of [thorn]u thou. See
   {Thou}, and cf. {Thy}.]
   A form of the possessive case of the pronoun thou, now
   superseded in common discourse by your, the possessive of
   you, but maintaining a place in solemn discourse, in poetry,
   and in the usual language of the Friends, or Quakers.

   Note: In the old style, thine was commonly shortened to thi
         (thy) when used attributively before words beginning
         with a consonant; now, thy is used also before vowels.
         Thine is often used absolutely, the thing possessed
         being understood.