Source : Webster's Revised Unabridged Dictionary (1913)

Youth \Youth\ ([=u]th), n.; pl. {Youths} ([=u]ths; 264) or
   collectively {Youth}. [OE. youthe, youh[thorn]e,
   [yogh]uhe[eth]e, [yogh]uwe[eth]e, [yogh]eo[yogh]e[eth]e, AS.
   geogu[eth], geogo[eth]; akin to OS. jug[eth], D. jeugd, OHG.
   jugund, G. jugend, Goth. junda. [root]281. See {Young}.]
   1. The quality or state of being young; youthfulness;
      juvenility. ``In my flower of youth.'' --Milton.

            Such as in his face Youth smiled celestial.
                                                  --Milton.

   2. The part of life that succeeds to childhood; the period of
      existence preceding maturity or age; the whole early part
      of life, from childhood, or, sometimes, from infancy, to
      manhood.

            He wondered that your lordship Would suffer him to
            spend his youth at home.              --Shak.

            Those who pass their youth in vice are justly
            condemned to spend their age in folly. --Rambler.

   3. A young person; especially, a young man.

            Seven youths from Athens yearly sent. --Dryden.

   4. Young persons, collectively.

            It is fit to read the best authors to youth first.
                                                  --B. Jonson.

Youth \Youth\ ([=u]th), n.; pl. {Youths} ([=u]ths; 264) or
   collectively {Youth}. [OE. youthe, youh[thorn]e,
   [yogh]uhe[eth]e, [yogh]uwe[eth]e, [yogh]eo[yogh]e[eth]e, AS.
   geogu[eth], geogo[eth]; akin to OS. jug[eth], D. jeugd, OHG.
   jugund, G. jugend, Goth. junda. [root]281. See {Young}.]
   1. The quality or state of being young; youthfulness;
      juvenility. ``In my flower of youth.'' --Milton.

            Such as in his face Youth smiled celestial.
                                                  --Milton.

   2. The part of life that succeeds to childhood; the period of
      existence preceding maturity or age; the whole early part
      of life, from childhood, or, sometimes, from infancy, to
      manhood.

            He wondered that your lordship Would suffer him to
            spend his youth at home.              --Shak.

            Those who pass their youth in vice are justly
            condemned to spend their age in folly. --Rambler.

   3. A young person; especially, a young man.

            Seven youths from Athens yearly sent. --Dryden.

   4. Young persons, collectively.

            It is fit to read the best authors to youth first.
                                                  --B. Jonson.

Source : WordNet®

youth
     n 1: a young person (especially a young man or boy) [syn: {young
          person}, {younker}, {spring chicken}]
     2: young people collectively; "rock music appeals to the
        young"; "youth everywhere rises in revolt" [syn: {young}]
        [ant: {aged}]
     3: the time of life between childhood and maturity
     4: early maturity; the state of being young or immature or
        inexperienced
     5: an early period of development; "during the youth of the
        project" [syn: {early days}]
     6: the freshness and vitality characteristic of a young person
        [syn: {youthfulness}, {juvenility}]