ac·cu·ra·cy  n.

1. Conformity to fact.

2. Precision; exactness.

3. The ability of a measurement to match the actual value of the quantity being measured.

pre·ci·sion  n.

1. The state or quality of being precise; exactness.

2.  

   1. The ability of a measurement to be consistently reproduced.

   2. The number of significant digits to which a value has been reliably measured.

Accuracy refers to how closely a measured value agrees with the correct value.

Precision refers to how closely individual measurements agree with each other.