牛蛙,菜蛙
Bullfrog \Bull"frog`\, n. (Zo["o]l.) A very large species of frog ({Rana Catesbiana}), found in North America; -- so named from its loud bellowing in spring.
bullfrog n : largest North American frog; highly aquatic with a deep-pitched voice [syn: {Rana catesbeiana}]