The answer to this question is no, not for all intents and purposes.
The technical definition of a Cantilever is a beam that carries the load to the support pole. It allows for an overhang without needing external bracing. The overhang is balanced by the weight and position fo the supporting structure. So the weight at the base at the bottom of the parasol might balance it, or the weight of the ground if the pole is inserted into the ground.
A lot of stress is found at the point where the overhanging beam meets the support structure. So a good cantilever has to be carefully designed and engineered to ensure that the stress point will be strong enough, and that the parasol is sufficiently well balanced to be stable. A centre pole parasol does not present these difficulties.
Most side post parasols are cantilevered. Some are variations – so the Shademakers Sola Parasol has 2 beams coming from the centre pole. Technically I believe that this is not a true cantilever as defined above, but nevertheless, the parasol canopy overhangs and has to be counter balanced by the pole and weight holding that pole.