Source : Webster's Revised Unabridged Dictionary (1913)

Old \Old\, a. [Compar. {Older}; superl. {Oldest}.] [OE. old,
   ald, AS. ald, eald; akin to D. oud, OS. ald, OFries. ald,
   old, G. alt, Goth. alpeis, and also to Goth. alan to grow up,
   Icel. ala to bear, produce, bring up, L. alere to nourish.
   Cf. {Adult}, {Alderman}, {Aliment}, {Auld}, {Elder}.]
   1. Not young; advanced far in years or life; having lived
      till toward the end of the ordinary term of living; as, an
      old man; an old age; an old horse; an old tree.

            Let not old age disgrace my high desire. --Sir P.
                                                  Sidney.

            The melancholy news that we grow old. --Young.

   2. Not new or fresh; not recently made or produced; having
      existed for a long time; as, old wine; an old friendship.
      ``An old acquaintance.'' --Camden.

   3. Formerly existing; ancient; not modern; preceding;
      original; as, an old law; an old custom; an old promise.
      ``The old schools of Greece.'' --Milton. ``The character
      of the old Ligurians.'' --Addison.

   4. Continued in life; advanced in the course of existence;
      having (a certain) length of existence; -- designating the
      age of a person or thing; as, an infant a few hours old; a
      cathedral centuries old.

            And Pharaoh said unto Jacob, How old art thou?
                                                  --Cen. xlvii.
                                                  8.

   Note: In this use old regularly follows the noun that
         designates the age; as, she was eight years old.

   5. Long practiced; hence, skilled; experienced; cunning; as,
      an old offender; old in vice.

            Vane, young in years, but in sage counsel old.
                                                  --Milton.

   6. Long cultivated; as, an old farm; old land, as opposed to
      {new} land, that is, to land lately cleared.

   7. Worn out; weakened or exhausted by use; past usefulness;
      as, old shoes; old clothes.

   8. More than enough; abundant. [Obs.]

            If a man were porter of hell gate, he should have
            old turning the key.                  --Shak.

   9. Aged; antiquated; hence, wanting in the mental vigor or
      other qualities belonging to youth; -- used disparagingly
      as a term of reproach.

   10. Old-fashioned; wonted; customary; as of old; as, the good
       old times; hence, colloquially, gay; jolly.

   11. Used colloquially as a term of cordiality and
       familiarity. ``Go thy ways, old lad.'' --Shak.

   {Old age}, advanced years; the latter period of life.

   {Old bachelor}. See {Bachelor}, 1.

   {Old Catholics}. See under {Catholic}.

   {Old English}. See under {English}. n., 2.

   {Old Nick}, {Old Scratch}, the devil.

   {Old lady} (Zo["o]l.), a large European noctuid moth ({Mormo
      maura}).

   {Old maid}.
       (a) A woman, somewhat advanced in years, who has never
           been married; a spinster.
       (b) (Bot.) A West Indian name for the pink-flowered
           periwinkle ({Vinca rosea}).
       (c) A simple game of cards, played by matching them. The
           person with whom the odd card is left is the old
           maid.

   {Old man's beard}. (Bot.)
       (a) The traveler's joy ({Clematis Vitalba}). So named
           from the abundant long feathery awns of its fruit.
       (b) The {Tillandsia usneoides}. See {Tillandsia}.

   {Old man's head} (Bot.), a columnar cactus ({Pilocereus
      senilis}), native of Mexico, covered towards the top with
      long white hairs.

   {Old red sandstone} (Geol.), a series of red sandstone rocks
      situated below the rocks of the Carboniferous age and
      comprising various strata of siliceous sandstones and
      conglomerates. See {Sandstone}, and the Chart of
      {Geology}.

   {Old school}, a school or party belonging to a former time,
      or preserving the character, manner, or opinions of a
      former time; as, a gentleman of the old school; -- used
      also adjectively; as, Old-School Presbyterians.

   {Old sledge}, an old and well-known game of cards, called
      also {all fours}, and {high, low, Jack, and the game}.

   {Old squaw} (Zo["o]l.), a duck ({Clangula hyemalis})
      inhabiting the northern parts of both hemispheres. The
      adult male is varied with black and white and is
      remarkable for the length of its tail. Called also
      {longtailed duck}, {south southerly}, {callow}, {hareld},
      and {old wife}.

   {Old style}. (Chron.) See the Note under {Style}.

   {Old Testament}. See under {Testament}.

   {Old wife}. [In the senses
       b and
       c written also {oldwife}.]
       (a) A prating old woman; a gossip.

                 Refuse profane and old wives' fables. --1 Tim.
                                                  iv. 7.
       (b) (Zo["o]l.) The local name of various fishes, as the
           European black sea bream ({Cantharus lineatus}), the
           American alewife, etc.
       (c) (Zo["o]l.) A duck; the old squaw.

   {Old World}, the Eastern Hemisphere.

   Syn: Aged; ancient; pristine; primitive; antique; antiquated;
        old-fashioned; obsolete. See {Ancient}.

Source : WordNet®

old school
     n : a class of people favoring traditional ideas