bullfrog

the word "bullfrog" is a transparent compound formed within english. the first element, "bull," is an old english term for the male bovine, which by the late 16th century had developed a figurative sense denoting anything large or loud, as seen in words like "bullfiddle" (bass viol) or "bulldog." the second element, "frog," is also of old english origin. when combined, the term literally means a "bull-like frog," a name coined to describe the notably large size and characteristically deep, loud croak of this north american amphibian species. it is a classic example of english compounding, where two native roots are joined to create a vivid, descriptive name for a natural species.

Structure: bull (large/bovine) + frog (amphibian) bull: from middle english bule, from old english bula, meaning "bull, male bovine," used here to denote large size or loud sound. frog: from old english frogga, frocga, meaning "frog, amphibian."