When used in relation to food, a truckle is generally a whole cylinder of cheese as sold by the cheesemaker, though it can also be a wheel.
In North America, people are more inclined to just say a “wheel” of cheese, even if it’s a cylinder.
A truckle, generally, is a small wheel or a caster. What North Americans would call a “trundle bed” (the kind of small bed on wheels that wheels under a large bed) people in the UK call a “truckle bed”.
A truckle is also a wooden tray that looks like a small sledge, with handles for lifting and carrying to the front and the back.