Source : Webster's Revised Unabridged Dictionary (1913)

Matrix \Ma"trix\, n.; pl. {Matrices}. [L., fr. mater mother. See
   {Mother}, and cf. {Matrice}.]
   1. (Anat.) The womb.

            All that openeth the matrix is mine.  --Ex. xxxiv.
                                                  19.

   2. Hence, that which gives form or origin to anything; as:
      (a) (Mech.) The cavity in which anything is formed, and
          which gives it shape; a die; a mold, as for the face
          of a type.
      (b) (Min.) The earthy or stony substance in which metallic
          ores or crystallized minerals are found; the gangue.
      (c) pl. (Dyeing) The five simple colors, black, white,
          blue, red, and yellow, of which all the rest are
          composed.

   3. (Biol.) The lifeless portion of tissue, either animal or
      vegetable, situated between the cells; the intercellular
      substance.

   4. (Math.) A rectangular arrangement of symbols in rows and
      columns. The symbols may express quantities or operations.

Source : WordNet®

matrix
     n 1: a rectangular array of elements (or entries) set out by rows
          and columns
     2: an enclosure within which something originates or develops
        (from the Latin for womb)
     3: the body substance in which tissue cells are embedded [syn:
        {intercellular substance}, {ground substance}]
     4: the formative tissue at the base of a nail
     5: mold used in the production of phonograph records, type, or
        other relief surface
     [also: {matrices} (pl)]

matrices
     See {matrix}