Canadian spelling differs slightly from both British and American English. Here are some common differences:
If using MS Word’s spell-checking tool, ensure that it is set to Canadian English—under Tools / Language / Set Language, check English (Canada). Beware that spell check will not flag words that are misspelled but that still happen to be words. If you intend to spell cause but neglect the u, for example, the resulting case is a word and will not be flagged as an error. See the “Exclusion Dictionary” section of the “Tools of the Trade” chapter for one way of avoiding these errors.
Sadly, the Canadian Oxford English Dictionary is no longer being actively updated and is now over 15 years old. So the primary dictionary employees should reference is the online version of Merriam-Webster. When it comes to spelling, words should be looked up using the following sources, in authority order (sources higher on the list supersede those below).