Source : Webster's Revised Unabridged Dictionary (1913)

Mother \Moth"er\, a.
   Received by birth or from ancestors; native, natural; as,
   mother language; also acting the part, or having the place of
   a mother; producing others; originating.

         It is the mother falsehood from which all idolatry is
         derived.                                 --T. Arnold.

   {Mother cell} (Biol.), a cell which, by endogenous divisions,
      gives rise to other cells (daughter cells); a parent cell.
      

   {Mother church}, the original church; a church from which
      other churches have sprung; as, the mother church of a
      diocese.

   {Mother country}, the country of one's parents or ancestors;
      the country from which the people of a colony derive their
      origin.

   {Mother liquor} (Chem.), the impure or complex residual
      solution which remains after the salts readily or
      regularly crystallizing have been removed.

   {Mother queen}, the mother of a reigning sovereign; a queen
      mother.

   {Mother tongue}.
   (a) A language from which another language has had its
       origin.
   (b) The language of one's native land; native tongue.

   {Mother water}. See {Mother liquor} (above).

   {Mother wit}, natural or native wit or intelligence.

Source : WordNet®

mother cell
     n : cell from which another cell of an organism (usually of a
         different sort) develops; "a sperm cell develops from a
         sperm mother cell"