NOUN (3)

1. a married woman (usually middle-aged with children) who is staid and dignified;

2. a wardress in a prison;

3. a woman in charge of nursing in a medical institution;

The Collaborative International Dictionary of English v.0.48:

Matron \Ma"tron\, n. [F. matrone, L. matrona, fr. mater mother.
   See Mother.]
   1. A wife or a widow, especially, one who has borne children;
      a woman of staid or motherly manners.
      [1913 Webster]

            Your wives, your daughters,
            Your matrons, and your maids.         --Shak.
      [1913 Webster]

            Grave from her cradle, insomuch that she was a
            matron before she was a mother.       --Fuller.
      [1913 Webster]

   2. A housekeeper; esp., a woman who manages the domestic
      economy of a public instution; a head nurse in a hospital;
      as, the matron of a school or hospital.
      [1913 Webster]

   Jury of matrons (Law), a jury of experienced women called
      to determine the question of pregnancy when set up in bar
      of execution, and for other cognate purposes.
      [1913 Webster]

WordNet (r) 3.0 (2006):

matron
    n 1: a married woman (usually middle-aged with children) who is
         staid and dignified
    2: a wardress in a prison
    3: a woman in charge of nursing in a medical institution

Moby Thesaurus II by Grady Ward, 1.0:

47 Moby Thesaurus words for "matron":
   Eve, Frau, abbess, better half, chatelaine, common-law wife,
   concubine, dame, daughter of Eve, distaff, domina, donna, dowager,
   feme, feme covert, femme, first lady, frow, gentlewoman, girl,
   goodwife, goody, governess, grande dame, great lady, helpmate,
   helpmeet, homemaker, housewife, lady, lass, madam, married woman,
   matriarch, milady, mistress, mother superior, old lady, old woman,
   rib, squaw, vrouw, wahine, weaker vessel, wedded wife, wife,
   woman



Bouvier's Law Dictionary, Revised 6th Ed (1856):

MATRON. A married woman, generally an elderly married woman.
     2. By the laws of England, when a widow feigns herself with child, in
order to exclude the next heir, and a suppositious birth is expected,
then, upon the writ de ventre inspiciendo, a jury of women is to be,
impanelled to try the question, whether with child or not. Cro, Eliz. 566.
So when a woman was sentenced to death, and she declared herself to be quick
with child, a jury of matrons is impanelled to try whether she be or be not
with child. 4 Bl. Com. 395. See Pregnancy; Quick with child.