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

bullfrog \bull"frog`\, n. zool.
   a very large species of frog rana catesbiana, found in
   north america; -- so named from its loud bellowing in spring.
   1913 webster
see also:
rana catesbiana 

Rana Catesbiana >> R Words
Rana Catesbiana, definition of term: Rana Catesbiana
rana+catesbiana_pag1.html

Rana >> R Words
Rana, definition of term: Rana
rana_pag1.html

Rana Pipiens >> R Words
Rana Pipiens, definition of term: Rana Pipiens
rana+pipiens_pag1.html