circular error

noun

1. Horology. loss of isochronism in a pendulum moving through circular arcs of different sizes: sometimes avoided by causing the pendulum to move through cycloidal arcs.
2. Military. error measured as the distance from the center of a target to the point of impact of a bomb or shell, or to the ground zero of an aerial burst.

Word History and Origins

Origin of circular error¹

First recorded in 1880–85