The Collaborative International Dictionary of English v.0.48:

matrix \ma"trix\ (m[=a]"tr[i^]ks), n.; pl. Matrices
   (m[a^]t"r[i^]*s[=e]z). [L., fr. mater mother. See Mother,
   and cf. Matrice.]
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   1. (Anat.) The womb.
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            All that openeth the matrix is mine.  --Ex. xxxiv.
                                                  19.
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   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.
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   3. (Biol.) The lifeless portion of tissue, either animal or
      vegetable, situated between the cells; the intercellular
      substance.
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   4. (Math.) A rectangular arrangement of symbols in rows and
      columns. The symbols may express quantities or operations.
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