Gobstopper and jawbreaker get treated as two different sweets by people who've only ever known one of the names, but they describe the same basic idea: a hard, layered candy built up in rounds and made to last, not to be bitten.
Same format, two names
Both are built the same way — a small core coated in layer after layer of hard sugar syrup, often in contrasting colours so the sweet changes shade as it slowly dissolves. The whole point, on either side of the Atlantic, is longevity: these are sweets designed to occupy your mouth for the best part of half an hour, not to be finished in a few bites.
Where "gobstopper" comes from
"Gob" is long-standing British slang for mouth, and a gobstopper does exactly what the name says — a sweet big and hard enough to keep your mouth occupied and, practically speaking, stop you talking with it in there. The name got a big boost in Britain from Roald Dahl's "Everlasting Gobstopper" in Charlie and the Chocolate Factory, which cemented the word for a generation who'd never have used 1920s sweet-shop slang otherwise.
Where "jawbreaker" comes from
The American name takes a different angle, focusing on hardness rather than mouth-filling size. It's a slightly tongue-in-cheek warning: bite down on one properly, rather than letting it dissolve, and you risk exactly what the name suggests. Jawbreaker became the standard US term for the same category of layered hard candy, largely independent of the British word.
The differences that did develop
Despite sharing a format, some real differences grew up either side of the naming split. Traditional British gobstoppers tend to be smaller and often flavoured with aniseed in their older varieties, historically sold loose from sweet-shop jars. American jawbreakers have tended toward larger sizes and, in some modern versions, a bubblegum or soft centre once you finally work through the hard layers — a variation that never really caught on under the gobstopper name. Both traditions still sit firmly in the same retro sweets category today.
Frequently asked questions
Is a gobstopper the same as a jawbreaker?
Yes, essentially — the same style of hard, layered, long-lasting candy, just with a British name and an American one.
Why is it called a gobstopper in the UK?
"Gob" is British slang for mouth — the sweet is named for stopping it up for a long stretch.
Why is it called a jawbreaker in the US?
It's a play on the sweet's hardness, suggesting it could hurt your jaw if you bit straight through it instead of letting it dissolve.