An Etymological Dictionary of Astronomy and Astrophysics

A point of discontinuity in a function or a derivative of a function.

Etymology (EN): Etymology unclear, probably akin to L.G. gumpen “to jump.”

Etymology (PE): Jaheš, verbal noun of jahidan, jastan “to jump, to leap,” from Mid.Pers. jastan, jahidan “to jump,” figuratively “to happen, occur;” Av. yaēš-, yas- “to boil;” cf. Skt. yas-, yásyati “to boil, to heat; to make effort.”