Precision

To illustrate the distinction, if you throw ten darts at the center of a dartboard, and they are scattered loosely around the center, your throws had high accuracy but low precision. If the darts are tightly grouped at a spot on the wall not very close to the dartboard, your throws had high precision but low accuracy.

In aviation, describes an instrument approach procedure which provides glidepath guidance in addition to horizontal guidance. Contrasts with a nonprecision approach, in which the pilot must determine glidepath by measuring time against a fixed descent rate.

Pre*ci"sion (?), n. [Cf. F. pr'ecision, L. praecisio a cutting off. See Precise.]

The quality or state of being precise; exact limitation; exactness; accuracy; strict conformity to a rule or a standard; definiteness.

I have left out the utmost precisions of fractions. Locke.

Syn. -- Preciseness; exactness; accuracy; nicety. -- Precision, Preciseness. Precision is always used in a good sense; as, precision of thought or language; precision in military evolutions. Preciseness is sometimes applied to persons or their conduct in a disparaging sense, and precise is often used in the same way.

© Webster 1913.