Source : Webster's Revised Unabridged Dictionary (1913)

Opening \O"pen*ing\, n.
   1. The act or process of opening; a beginning; commencement;
      first appearance; as, the opening of a speech.

            The opening of your glory was like that of light.
                                                  --Dryden.

   2. A place which is open; a breach; an aperture; a gap;
      cleft, or hole.

            We saw him at the opening of his tent. --Shak.

   3. Hence: A vacant place; an opportunity; as, an opening for
      business. [Colloq.] --Dickens.

   4. A thinly wooded space, without undergrowth, in the midst
      of a forest; as, oak openings. [U.S.] --Cooper.

Open \O"pen\ v. t. [imp. & p. p. {Opened}; p. pr. & vb. n.
   {Opening}.] [AS. openian. See {Open},a.]
   1. To make or set open; to render free of access; to unclose;
      to unbar; to unlock; to remove any fastening or covering
      from; as, to open a door; to open a box; to open a room;
      to open a letter.

            And all the windows of my heart I open to the day.
                                                  --Whittier.

   2. To spread; to expand; as, to open the hand.

   3. To disclose; to reveal; to interpret; to explain.

            The king opened himself to some of his council, that
            he was sorry for the earl's death.    --Bacon.

            Unto thee have I opened my cause.     --Jer. xx. 12.

            While he opened to us the Scriptures. --Luke xxiv.
                                                  32.

   4. To make known; to discover; also, to render available or
      accessible for settlements, trade, etc.

            The English did adventure far for to open the North
            parts of America.                     --Abp. Abbot.

   5. To enter upon; to begin; as, to open a discussion; to open
      fire upon an enemy; to open trade, or correspondence; to
      open a case in court, or a meeting.

   6. To loosen or make less compact; as, to open matted cotton
      by separating the fibers.

   {To open one's mouth}, {to speak}.

   {To open up}, to lay open; to discover; to disclose.

            Poetry that had opened up so many delightful views
            into the character and condition of our ``bold
            peasantry, their country's pride.''   --Prof.
                                                  Wilson.

Source : WordNet®

opening
     adj : first or beginning; "the memorable opening bars of
           Beethoven's Fifth"; "the play's opening scene" [ant: {closing}]

opening
     n 1: an open or empty space in or between things; "there was a
          small opening between the trees"; "the explosion made a
          gap in the wall" [syn: {gap}]
     2: a ceremony accompanying the start of some enterprise
     3: becoming open or being made open; "the opening of his arms
        was the sign I was waiting for"
     4: the first performance (as of a theatrical production); "the
        opening received good critical reviews" [syn: {opening
        night}, {curtain raising}]
     5: the act of opening something; "the ray of light revealed his
        cautious opening of the door" [ant: {shutting}]
     6: opportunity especially for employment or promotion; "there
        is an opening in the sales department"
     7: the initial part of the introduction; "the opening
        established the basic theme"
     8: a possible alternative; "bankruptcy is always a possibility"
        [syn: {possibility}, {possible action}]
     9: an aperture or hole opening into a bodily cavity; "the
        orifice into the aorta from the lower left chamber of the
        heart" [syn: {orifice}, {porta}]
     10: a vacant or unobstructed space that is man-made; "they left
         a small opening for the cat at the bottom of the door"
     11: an entrance equipped with a hatch; especially a passageway
         between decks of a ship [syn: {hatchway}, {scuttle}]
     12: the first of a series of actions; "he memorized all the
         important chess openings" [syn: {first step}, {initiative},
          {opening move}]