https://www.cbc.ca/news/politics/trudeau-gun-control-measures-ban-1.5552131
The term "assault-style" has no legal definition in Canada. The Firearms Act also does not currently classify firearms as "military-style" — that term would have to be defined in the new regulations.
Generally speaking, an assault-style weapon is a semi-automatic firearm with an ammunition magazine, built to fire quickly. There is already a legal limit — five rounds — on the maximum size of a magazine.