The rules split movement into three groups: Normal moves (done in the movement phase, includes retreating and running), charge moves and pile in moves. All of them are considered to be "moves". Some abilities specify something like "after a charge move", which is triggered after that specific type, others, like the eternal guard, simply save if they have not made a "move". This means they literally cannot move, in any of the ways specified. With Cage of Thorns, it just says "when this unit moves" or something like that, which means the first time is makes ANY kind of "move". Another example is the Flamespyre pheonnix's Wake of Fire ability, which specifies "After this unit has made a normal move", so charge moves and pile in moves do not count for the purposes of the rule. If it had said "after this model has made a move" then all types would count. I hope that makes sense.