The Province of Quebec defines "ice cider" by regulation:
“ice cider: cider obtained by the fermentation of juice of apples that has a pre-fermentation sugar content of not less than 30° Brix achieved solely by natural cold, producing a finished product with a residual sugar content of not less than 130 g per litre and an actual alcoholic strength of more than 7% by volume but not more than 13% by volume."
Many producers and Canadian provincial liquor control boards have adopting this definition.
The "natural cold" requirement can be achieved by freezing the juice after it is pressed or freezing the apples (before or after picking). In all cases, you must rely on outside temperatures, which of course severely limits producers in mild climates.
When you see the term, "iced cider" in Canada, it is an indication that the Quebec regulation has not been met.
For example Double Cross Cidery presses their apples then they freeze the juice in 20 litre pails in a large walk in freezer. When the juice is thawed, the first thing that melts is the sugar. This concentrate is drawn off and then slowly fermented to create Double Cross Iced Ciders.
Georgian Hills Vineyards has taken a different approach by trademarking their own term, "frozen to the core."
From a pure stylistic point of view, I believe it needs to be the cider makers choice. I don’t like the idea of being told what maximun brix or alcohol I am required to have so I would most definately make “iced” cider.
As a small producer, maintaining control opens up more possibilities to create different variants and ultimate a better quality product.
There are many aspects of the beverage alcohol business that are over regulated. This is one of those cases. As the apple cider business grows I suspect you will see more and more trademarked names used for iced cider creations.