I think the difference between urban and suburban is like the diffference between man and woman.
As I suggested, the word "urban" can also include the suburbs. The word "man" is the same way. It can refer to men as a gender. Or it can refer to the human race overall, which does include women as well, even if at times we as men cannot understand them and they seem like a different species.
Imagine if the title of the movie Children of Men only refered to "Men" as a gender only. How do men conceive a child without women? If that was the case, the movie would have been a lot more like that Arnold Schwarzenegger movie, and it would be very different, you might agree.
I think all built-up areas in the GTA can be considered to be part of "urban Toronto." All parts of urban Toronto have some urban quality, but some areas have less urban qualities than others, hence the term suburban. Does anyone here truly believe that Mississauga or Pickering is completely devoid of any urban qualities? Do you truly believe that Mississauga and Pickering are completely devoid of any resemblence of high density, transit, mixed use developments, pedestrians, or whatever other quality you associate truly urban places? If so, I think that is very ignorant.