An abrupt change in the shape of a waveguide. Also known as waveguide discontinuity.

1. An interruption in sedimentation.

2. A surface that separates unrelated groups of rocks.

A boundary at which the velocity of seismic waves changes abruptly.

A point at which a function is not continuous.

The place where the structural nature of a weldment is interfered with because of the materials involved or where the mechanical, physical, or metallurgical aspects are not homogeneous.

A break in the continuity of a medium or material at which a reflection of wave energy can occur.