The terms accuracy and precision have different meanings in the context of measurement.

Accuracy is the difference between your reported measurement and the true (but unknown) measurement. It is generally imposible to calculate the accuracy of a measurement, because it requires us to know the true measurement.

Precision refers to the perceived level of accuracy of a measuring tool.We generally assume a measurement tool, such as a ruler, with a greater degree of precision (that is, smaller units or more closely spaced marked) results in measurement with a greater degree of exactness (because we perceive there will be less rounding error).