1. [n]  a woman of refinement; "a chauffeur opened the door of the limousine for the grand lady"
2. [n]  (United Kingdom) a woman of the peerage in Britain
3. [n]  a polite name for any woman; "a nice lady at the library helped me"

Lady
In Manchester, England, when a seventeen-year-old girl who hasn't been acting like herself lately is turned into the very creature she has personified, she isn't sure that the change is all bad.

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1. \La"dy\, n.; pl. {Ladies}. [OE. ladi, l[ae]fdi, AS.
   hl?fdige, hl?fdie; AS. hl[=a]f loaf + a root of uncertain
   origin, possibly akin to E. dairy. See {Loaf}, and cf.
   {Lord}.]
   1. A woman who looks after the domestic affairs of a family;
      a mistress; the female head of a household.
            Agar, the handmaiden of Sara, whence comest thou,
            and whither goest thou? The which answered, Fro the
            face of Sara my lady.                 --Wyclif (Gen.
                                                  xvi. 8.).
   2. A woman having proprietary rights or authority; mistress;
      -- a feminine correlative of lord. ``Lord or lady of high
      degree.'' --Lowell.
            Of all these bounds, even from this line to this, .
            . . We make thee lady.                --Shak.
   3. A woman to whom the particular homage of a knight was
      paid; a woman to whom one is devoted or bound; a
      sweetheart.
            The soldier here his wasted store supplies, And
            takes new valor from his lady's eyes. --Waller.
   4. A woman of social distinction or position. In England, a
      title prefixed to the name of any woman whose husband is
      not of lower rank than a baron, or whose father was a
      nobleman not lower than an earl. The wife of a baronet or
      knight has the title of Lady by courtesy, but not by
      right.
   5. A woman of refined or gentle manners; a well-bred woman;
      -- the feminine correlative of gentleman.
   6. A wife; -- not now in approved usage. --Goldsmith.
   7. (Zo["o]l.) The triturating apparatus in the stomach of a
      lobster; -- so called from a fancied resemblance to a
      seated female figure. It consists of calcareous plates.
   {Ladies' man}, a man who affects the society of ladies.
   {Lady altar}, an altar in a lady chapel. --Shipley.
   {Lady chapel}, a chapel dedicated to the Virgin Mary.
   {Lady court}, the court of a lady of the manor.
   {Lady court}, the court of a lady of the manor.
   {Lady crab} (Zo["o]l.), a handsomely spotted swimming crab
      ({Platyonichus ocellatus}) very common on the sandy shores
      of the Atlantic coast of the United States.
   {Lady fern}. (Bot.) See {Female fern}, under {Female}, and
      Illust. of {Fern}.
   {Lady in waiting}, a lady of the queen's household, appointed
      to wait upon or attend the queen.
   {Lady Mass}, a Mass said in honor of the Virgin Mary.
      --Shipley.
   {Lady of the manor}, a lady having jurisdiction of a manor;
      also, the wife of a manor lord.
   {Lady's maid}, a maidservant who dresses and waits upon a
      lady. --Thackeray.
   {Our Lady}, the Virgin Mary.
   

2. \La"dy\, a.
   Belonging or becoming to a lady; ladylike. ``Some lady
   trifles.''                                     --Shak.
   

3. \La"dy`\
   The day of the annunciation of the Virgin Mary, March 25. See
   {Annunciation}.
   

["Key Concepts in the INCAS Multicomputer Project", J. Nehmer et al IEEE Trans Soft Eng SE-13(8):913-923 (Aug 1987)].