discontinuity

noun3

1. •
   A lack of continuity, regularity or sequence; a break or gap.

   • The data shows a clear discontinuity in temperature around 1990.
   • Geologists noted a discontinuity between the two rock layers.
2. •
   A point in the range of a function at which it is undefined or discontinuous.
3. •
   a subterranean interface at which seismic velocities change