The Collaborative International Dictionary of English v.0.48:

Vanity \Van"i*ty\, n.; pl. Vanities. [OE. vanite, F.
   vanit['e], L. vanitas, fr. vanus empty, vain. See Vain.]
   [1913 Webster]
   1. The quality or state of being vain; want of substance to
      satisfy desire; emptiness; unsubstantialness; unrealness;
      falsity.
      [1913 Webster]

            Vanity of vanities, saith the Preacher, vanity of
            vanities; all is vanity.              --Eccl. i. 2.
      [1913 Webster]

            Here I may well show the vanity of that which is
            reported in the story of Walsingham.  --Sir J.
                                                  Davies.
      [1913 Webster]

   2. An inflation of mind upon slight grounds; empty pride
      inspired by an overweening conceit of one's personal
      attainments or decorations; an excessive desire for notice
      or approval; pride; ostentation; conceit.
      [1913 Webster]

            The exquisitely sensitive vanity of Garrick was
            galled.                               --Macaulay.
      [1913 Webster]

   3. That which is vain; anything empty, visionary, unreal, or
      unsubstantial; fruitless desire or effort; trifling labor
      productive of no good; empty pleasure; vain pursuit; idle
      show; unsubstantial enjoyment.
      [1913 Webster]

            Vanity of vanities, saith the Preacher. --Eccl. i.
                                                  2.
      [1913 Webster]

            Vanity possesseth many who are desirous to know the
            certainty of things to come.          --Sir P.
                                                  Sidney.
      [1913 Webster]

            [Sin] with vanity had filled the works of men.
                                                  --Milton.
      [1913 Webster]

            Think not, when woman's transient breath is fled,
            That all her vanities at once are dead;
            Succeeding vanities she still regards. --Pope.
      [1913 Webster]

   4. One of the established characters in the old moralities
      and puppet shows. See Morality, n., 5.
      [1913 Webster]

            You . . . take vanity the puppet's part. --Shak.
      [1913 Webster]

   5. same as dressing table.
      [PJC]

   6. A cabinet built around a bathroom sink, usually with a
      countertop and sometimes drawers.
      [PJC]

   Syn: Egotism; pride; emptiness; worthlessness;
        self-sufficiency. See Egotism, and Pride.
        [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dressing table \Dressing table\, n.
   a table, usually having a vertical back piece containing a
   mirror, at which a person may sit while dressing or applying
   makeup, and on which articles for the toilet stand. It often
   has drawers for toiletries, clothing, or accessories. It is
   also called a vanity or vanity table.
   [PJC]

WordNet (r) 3.0 (2006):

vanity
    n 1: feelings of excessive pride [syn: amour propre,
         conceit, self-love, vanity]
    2: the quality of being valueless or futile; "he rejected the
       vanities of the world" [syn: vanity, emptiness]
    3: the trait of being unduly vain and conceited; false pride
       [syn: conceit, conceitedness, vanity] [ant:
       humbleness, humility]
    4: low table with mirror or mirrors where one sits while
       dressing or applying makeup [syn: dressing table,
       dresser, vanity, toilet table]

The Devil's Dictionary (1881-1906):

VANITY, n.  The tribute of a fool to the worth of the nearest ass.

    They say that hens do cackle loudest when
        There's nothing vital in the eggs they've laid;
        And there are hens, professing to have made
    A study of mankind, who say that men
    Whose business 'tis to drive the tongue or pen
        Make the most clamorous fanfaronade
        O'er their most worthless work; and I'm afraid
    They're not entirely different from the hen.
    Lo! the drum-major in his coat of gold,
        His blazing breeches and high-towering cap --
    Imperiously pompous, grandly bold,
        Grim, resolute, an awe-inspiring chap!
    Who'd think this gorgeous creature's only virtue
    Is that in battle he will never hurt you?
                                                     Hannibal Hunsiker