Answer: accuracy
Justification:
Any measure of a physical data is subject to errors. The errors can be of different kind.
The closer is a measure to the real or accepted value the more accurate the measure is.
For example, if you measure the length of a sheet of paper letter size and you know that the accepted value is 11 inches, then you can tell how accurate your measure is comparing with 11 inches.
Many times the measure is affected by the accuracy of the instrument used (the divisions), but it is also subject to human errors, and may be errors due to the method of measuring.