One of the challenges of living in Canada is trying to know what spelling to use. For some words, we use the American spelling (e.g. analyze, tire), and for others, we use the British spelling (e.g. metre, catalogue). In some cases, either is acceptable (e.g. colour and colour, theatre and theater), and yet in some others, we used to use the British spelling, but now the American spelling is more popular (e.g. encyclopaedia, airplane).
One word that confuses a lot of people is “defence”. Or is it “defense”? See? That’s the problem.
“Defence” is the spelling used throughout the Commonwealth, “defense” is the spelling used in the United States. An easy trick to help Canadians remember which to use is to just remember “C for Canada”.