Wikipedia
Canada Day is the national day of Canada. A federal statutory holiday, it celebrates the anniversary of the July 1, 1867, enactment of the Constitution Act, 1867 (then called the British North America Act, 1867), which united the three separate colonies of the Province of Canada, Nova Scotia, and New Brunswick into a single Dominion within the British Empire called Canada. Originally called Dominion Day , the holiday was renamed in 1982, the year the Canada Act was passed. Canada Day celebrations take place throughout the country, as well as in various locations around the world, attended by Canadians living abroad.
Usage examples of "canada day".
I only knew that it was Canada Day because, in my memory, I could see a cake in the shape of the flag.