A particular form of attire worn by females that includes a denim skirt paired with a denim jacket. A denim shirt worn under the jacket is optional, but does not add any level of authenticity. Often described as the female version of the "Canadian tuxedo". Originated circa 1989.
See Becky's outfit when going to the mall in Roseanne episode: "House of Grown-ups". Darlene should have said: "You're going to wear your Canadian wedding dress to the mall? Don't you think you're a little over dressed?"
When a couple unexpectedly get pregnant and they say, "Why not?" and just move in together and maybe a few years down the road quietly get married and nobody says much aboot it. Eh?
"So how did you two meet?" "Oh, we were drunk and our birth control failed, eh? So we figured we'd have a Canadian shotgun wedding."
"Will there be a lot of people at your wedding?" "No, just immediate family, eh?. Didn't want to make a big fuss 'cause it's a Canadian shotgun wedding."