An Etymological Dictionary of Astronomy and Astrophysics

A break in sequence or continuity of anything. → Balmer discontinuity
Math.: A point at which a function is not continuous.
Geology: A surface separating rock layers of differing properties or compositions.

Etymology (EN): M.L. discontinuitas, from discontinuus, from → dis- + continuus, → continuous.

Etymology (PE): Nâpeyvastegi, noun from nâpeyvasté “discontinuous,” from nâ- “non, un-,” → a-, + peyvasté,
→ continuous.