What does bullfrog mean?
A bullfrog is a large, robust frog best known for its deep, resonant call, which has been likened to the bellowing of a bull — hence the name. The term applies most precisely to the American bullfrog (Lithobates catesbeianus), the largest frog native to North America, but in looser usage, particularly in Britain, it can refer to any notably big frog. Bullfrogs are aquatic, favouring ponds, lakes, and slow-moving streams, where their low-pitched calls carry long distances on warm nights. The word is neutral in tone and common in both scientific and casual contexts, appearing frequently in nature writing and children's literature alike. Figuratively, 'bullfrog' can describe a deep, booming human voice. Because of the animal's size and appetite — it is a famously indiscriminate eater — the bullfrog also features prominently in ecological discussions, since introduced populations outside North America have become invasive in parts of Europe, Asia, and South America.
nounA large, deep-voiced frog, especially the North American species Lithobates catesbeianus (formerly Rana catesbeiana), the largest frog native to that continent. The name refers to its low, resonant call, which resembles the bellowing of a bull.
- A large, powerful frog with a deep resonant call; specifically the North American Lithobates catesbeianus.
"At dusk, the pond echoed with the booming calls of bullfrogs."
"Fishermen often hear bullfrogs calling across the lake on summer evenings."
"The bullfrog sat motionless among the reeds, half-submerged in the shallows."
Standard regular plural; used when referring to multiple individuals of any bullfrog species.
"Dozens of bullfrogs gathered at the edge of the marsh after sunset."
The American bullfrog is so voracious it will eat anything that fits in its mouth — including other frogs, snakes, and even small birds.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bullfrog
The word bullfrog is an English compound formed from 'bull' + 'frog', first recorded in English around the late 17th century. The name derives directly from the animal's characteristic deep, bellowing call, which reminded early observers of a bull's lowing. It belongs to a wider family of English compounds using 'bull' to denote something large, loud, or forceful, such as bulldog and bullfinch.
How bullfrog is actually used
Informal to neutral register. In everyday British English, 'bullfrog' may loosely describe any large frog, while in North American usage it typically denotes the specific species. The word carries no strong connotations, though its association with loud, resonant calls makes it useful figuratively for describing deep, booming voices.
Easily confused with bullfrog
A toad is generally a dry, warty-skinned amphibian that walks or hops short distances, whereas a bullfrog is a smooth-skinned, aquatic frog noted for its size and powerful swimming.