An Etymological Dictionary of Astronomy and Astrophysics

1. A deviation from accuracy or correctness; a mistake.
   

2. Physics: The difference between the calculated or observed value and the true value of a quantity. See also:
   → absolute error, → bias error, → calibration error, → cascade error, → error bar, → fitting error, → instrument error, → observational error, → probable error (PE), → random error, → relative error, → root-mean-square error, → sampling error, → standard error, → systematic error, → Type I error, → Type II error.

Etymology (EN): From O.Fr. erreur, from L. errorem (nom. error) “a wandering, straying, mistake,” from errare “to wander.”

Etymology (PE): Irang, from Mid.Pers. êrang “error, mistake;” xatâ, from Ar.