Source : Webster's Revised Unabridged Dictionary (1913)

Mater \Ma"ter\, n. [L., mother. See {Mother}.]
   See {Alma mater}, {Dura mater}, and {Pia mater}.

Source : WordNet®

mater
     n : informal terms for a mother [syn: {ma}, {mama}, {mamma}, {mom},
          {momma}, {mommy}, {mammy}, {mum}, {mummy}]