Lack of connection or continuity

Continuous functions are of utmost importance in mathematics, functions and applications.

A casting defect is an undesired irregularity in a metal casting process.

Frontier between rock layers with different properties inside the planet Earth

Discontinuity and continuity according to Michel Foucault reflect the flow of history and the fact that some "things are no longer perceived, described, expressed, characterised, classified, and known in the same way" from one era to the next.

A signal travelling along an electrical transmission line will be partly, or wholly, reflected back in the opposite direction when the travelling signal encounters a discontinuity in the characteristic impedance of the line, or if the far end of the line is not terminated in its characteristic impedance.

A discontinuity in geotechnical engineering is a plane or surface that marks a change in physical or chemical characteristics in a soil or rock mass. A discontinuity can be, for example, a bedding, schistosity, foliation, joint, cleavage, fracture, fissure, crack, or fault plane.

In linguistics, a discontinuity occurs when a given word or phrase is separated from another word or phrase that it modifies in such a manner that a direct connection cannot be established between the two without incurring crossing lines in the tree structure.