the quality of being near to the true value; "he was beginning to doubt the accuracy of his compass"; "the lawyer questioned the truth of my account" [ant: inaccuracy]
2.
(mathematics) the number of significant figures given in a number; "the atomic clock enabled scientists to measure time with much greater accuracy"
Ac"cu*ra*cy\ (#; 277), n. [See Accurate.] The state of being accurate; freedom from mistakes, this exemption arising from carefulness; exact conformity to truth, or to a rule or model; precision; exactness; nicety; correctness; as, the value of testimony depends on its accuracy. The professed end [of logic] is to teach men to think, to judge, and to reason, with precision and accuracy. --Reid. The accuracy with which the piston fits the sides. --Lardner.