n. — Food, especially Manitoba, Northwestern Ontario
a doughnut filled with jelly.
Type: 5. Frequency — This meaning of jambuster, which is unrelated to previous meanings, is a Canadian innovation. In the UK and the US, jambuster is used in contexts of new infrastructure designed to reduce traffic congestion, dating back to the 1950s in the case of the latter.
Jambuster 'donut' is used in Manitoba; the term is enregistered as Manitoban (see the 2005 quotation) and is also used in Ontario (see the 1998 quotation). The earliest known newspaper citation is from 1994. Jambuster is most prevalent in Canada according to internet domain searches (see Charts 1 and 2), with the spelling donut being more frequent in this connection in Canada than in the US (see also bismarck, Charts 1 & 2).
See also COD-2, s.v. "jambuster", which is marked "Cdn (Man. & NW Ont.)".
See also: bismarck Burlington bun Timbits (meaning 1)
- Methodological note: A regional chart is, unfortunately, not possible with our current digital resources (SD, June 2016).
- 1994  'Well,' I said, 'it sounds like a jelly doughnut.'
'Precisely,' she said. 'That's what everyone says in Ontario.'
But not in Winnipeg. There they step to the counter and ask for a jambuster.
Go a little further west, to Saskatchewan. And there you will hear the customers calling out for bismarcks. Same gooey doughnut, different name.
But in the dictionary business, you need proof. Written proof. 
- 1998  By the way, Burlington bun is an old Nova Scotia term for what Canadians elsewhere call a jambuster, a bismark or the more prosaic jelly doughnut. 
- 2005  While such toothsome technology is years away for us mere civilians, we have Splash to tide us over. Launched this fall, Trident's newest gum is the equivalent of a bismarck doughnut (or jambuster to you Manitobans and Ontarians). On the outside it's a Chiclet shell, inside it's liquidy goodness. 
- 2006  Jelly doughnut, usually covered in icing sugar.
- 2011  To a Winnipegger, it's a jambuster. To the rest of us, it's a jelly doughnut. 
- 2015  The doughnuts are about a third bigger than normal and that's just from air. The jambusters? The texture is like angel food cake. You could sop up an oil spill with the thing.