The Accuracy measures the degree of proximity between the result of a simulation to the results of a realistic experimental measurement.
Example Accuracy for a Model
If we use Newtonian mechanics as the model, then the Accuracy would be limited by the relativistic effects - for example, for a spaceship traveling close to the speed of light it is important to introduce corrections beyond the Newtonian laws, because the accuracy of it does not match experimentally-found relativistic flight trajectories.
Accuracy vs. Precision¶
Although Accuracy and Precision are often used interchangeably, they have different meanings.
Precision is a numerical characteristic of the Method, intended as a particular computational implementation of the Model, and is therefore directly dependent on the choice of input compute parameters.
Accuracy is a direct property of the theoretical Model itself, and can be thought about as a limit for when all computational parameters are set to their optimum values, thus yielding full-precision calculations.