Jump is the small, upward angle a gun leaps through as it is fired. It is a factor that may require consideration in gunnery or in creating Range Tables.
Prior to 1900, British gun sights were graduated to allow for jump. After 1900, however, improvements in the rigidity of their naval gun mountings was such that jump was no longer considered in the construction of sights.
- Manual of Gunnery (Volume I. Part I.) for His Majesty's Fleet, 1907. p. 35.