The Collaborative International Dictionary of English v.0.48:

Tomcod \Tom"cod`\ (t[o^]m"k[o^]d`), n. [Tom (see Tomboy) +
   cod: cf. F. tacaud whiting pout, American Indian tacaud,
   literally, plenty fish.] (Zool.)
   (a) A small edible American fish (Microgadus tomcod) of the
       Codfish family, very abundant in autumn on the Atlantic
       coast of the Northen United States; -- called also
       frostfish. See Illust. under Frostfish.
   (b) The kingfish. See Kingfish
   (a) .
   (c) The jack. See 2d Jack, 8.
   (c) .
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Cod \Cod\, n. [Cf. G. gadde, and (in Heligoland) gadden, L.
   gadus merlangus.] (Zool.)
   An important edible fish (Gadus morrhua), taken in immense
   numbers on the northern coasts of Europe and America. It is
   especially abundant and large on the Grand Bank of
   Newfoundland. It is salted and dried in large quantities.
   [1913 Webster]

   Note: There are several varieties; as shore cod, from
         shallow water; bank cod, from the distant banks; and
         rock cod, which is found among ledges, and is often
         dark brown or mottled with red. The tomcod is a
         distinct species of small size. The bastard, blue,
         buffalo, or cultus cod of the Pacific coast belongs
         to a distinct family. See Buffalo cod, under
         Buffalo.
         [1913 Webster]

   Cod fishery, the business of fishing for cod.

   Cod line, an eighteen-thread line used in catching codfish.
      --McElrath.
      [1913 Webster]