The Collaborative International Dictionary of English v.0.48:

Pondfish \Pond"fish`\, n. (Zool.)
   Any one of numerous species of American fresh-water fishes
   belonging to the family Centrarchid[ae]; -- called also
   pond perch, and sunfish.
   [1913 Webster]

   Note: The common pondfish of New England (Lepomis gibbosus)
         is called also bream, pumpkin seed, and sunny.
         See Sunfish. The long-eared pondfish (Lepomis
         auritus) of the Eastern United States is distinguished
         by its very long opercular flap.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Pumpkin \Pump"kin\, n. [For older pompion, pompon, OF. pompon,
   L. pepo, peponis, Gr. ?, properly, cooked by the sun, ripe,
   mellow; -- so called because not eaten till ripe. Cf. Cook,
   n.] (Bot.)
   A well-known trailing plant (Cucurbita pepo) and its fruit,
   -- used for cooking and for feeding stock; a pompion.
   [1913 Webster]

   Pumpkin seed.
   (a) The flattish oval seed of the pumpkin.
   (b) (Zool.) The common pondfish.
       [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Sunfish \Sun"fish`\, n. (Zool.)
   (a) A very large oceanic plectognath fish (Mola mola, Mola
       rotunda, or Orthagoriscus mola) having a broad body
       and a truncated tail.
   (b) Any one of numerous species of perch-like North American
       fresh-water fishes of the family Centrachidae. They
       have a broad, compressed body, and strong dorsal spines.
       Among the common species of the Eastern United States are
       Lepomis gibbosus (called also bream, pondfish,
       pumpkin seed, and sunny), the blue sunfish, or
       dollardee (Lepomis pallidus), and the long-eared
       sunfish (Lepomis auritus). Several of the species are
       called also pondfish.
   (c) The moonfish, or bluntnosed shiner.
   (d) The opah.
   (e) The basking, or liver, shark.
   (f) Any large jellyfish.
       [1913 Webster]

WordNet (r) 3.0 (2006):

pumpkin seed
    n 1: the edible seed of a pumpkin