[1] : 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
see also:
cook cucurbita pepo pumpkin seed 

[2] : The Collaborative International Dictionary of English v.0.48

crookneck \crook"neck`\, n.
   either of two varieties of squash, distinguished by their
   tapering, recurved necks. the summer crookneck is
   botanically a variety of the pumpkin cucurbita pepo and
   matures early in the season. it is pale yellow in color, with
   warty excrescences. the winter crookneck belongs to a
   distinct species cucurbita moschata and is smooth and
   often striped. u. s.

   syn: crookneck squash.
        webster 1913 suppl.
see also:
summer crookneck cucurbita pepo winter crookneck cucurbita moschata 

[3] : WordNet (r) 2.0

cucurbita pepo
     n : a coarse vine widely cultivated for its non-keeping large
         pulpy round orange fruit with firm orange skin and
         numerous seeds; subspecies of cucurbita pepo include the
         summer squashes and a few autumn squashes syn: pumpkin,
          pumpkin vine, autumn pumpkin
see also:
pumpkin pumpkin vine autumn pumpkin 

Pepo >> P Words
Pepo, definition of term: Pepo
pepo_pag1.html

Cucurbita >> C Words
Cucurbita, definition of term: Cucurbita
cucurbita_pag1.html