An interruption of the typical structure of a weldment, such as lack of homogeneity in the mechanical, metallurgical, or physical characteristics of the material or weldment A discontinuity is not necessarily a defect
A sudden or rapid change in physical properties of rocks within the Earth Discontinuities are recognized by seismic data See also: Mohorovicic discontinuity
Any interruption in sedimentation, whatever its cause or length, usually a manifestation of nondeposition and accompanying erosion
(I'm still working on this one but its my educated guess that it's a discontinuation of your present time-space when you do time travel)
A major shift in a trend, that is so drastic that it cannot be accounted for by normal variation An example might be the population shifts due to the baby boom A larger scale example would be change from the industrial revolution to the information revolution
Comparatively large contrast in meteorological elements over a relatively small distance or period of time In oceanography, it is the abrupt change or jump of a variable at a line or surface