Thanks Woody, yes it is, in part a question of definition.

Surely discussion of that definition is one of the functions of such forums as this?

Uncertainty is definitely linked to probability.

Probability is a definite number (one numebr) between 0 and 1

So it is tempting to think that if the probability is p then the uncertainty can be defined as (1-p), but this doesn't really work.

To add more to my examples.

Let my cube be a model of my car and of side L.

Now the UK rules for parking said car state that if any part of the car is on a yellow line it is illegally parked and I could be subject to a fine (or worse).

So what is the allowable uncertainty in positioning my car when I park it?

Now let my cube be much smaller.

Let it be the rider on a beam balance.

What is the uncertainty in positioning this rider so that the balance operates correctly?

In both cases the uncertainty could be huge.

The car could be 100 miles form the nearest yellow line.

But there is a minimum distance for palcing the centre.

Which brings out another point.

Probability is just a number. It has no units or dimensions.

Uncertainty is usually expressed in the units of the measurand and generally has dimensions.