Source : Webster's Revised Unabridged Dictionary (1913)

Lady \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.

Source : WordNet®

lady's maid
     n : a maid who is a lady's personal attendant