One of the challenges of Canadian English is that it incorporates British English while simultaneously incorporating American English. This is particularly confusing when it comes to choosing which words to use.
Take the words “center” and “centre”, for example.
Centre
Speakers of British English use the centre spelling when referring to something that is in the middle.
Center
American English speakers, on the other hand, use the center spelling.
So, where do Canadians come in? Do we side with Americans as we do with tire and curb, or do we side with the British as we do with colour and metre?
Well, in this case, in Canada, we use centre, just like the Brits.
Now, keep in mind, as with some other words, this usage is changing. Just as how the American spelling of color and pronunciation of zee are starting to gain popularity in Canada, so is the American usage of center. In time, Canadians may end up favouring the simpler approach.
But for now, in Canada, use centre.