Canadian whisky, as you might expect, is produced in Canada. It typically (but not always) is a blended whisky, and usually contains a high percentage of corn or corn based spirits. It is seen as lighter and smoother than other whisky styles, and thus is usually preferred for sipping, and it is not generally adopted for mixing in cocktails.
Many will incorrectly refer to Canadian whisky as "Rye", even though few Canadian whiskies meet the US requirement for using 51% or more rye in their grain bill. Even so, Canadian law allows distiller there to refer to their product as "Canadian Rye Whisky" (when sold within Canada), but when exported the "Rye" labeling has to be removed.