The Probert Encyclopaedia of Rocks & Minerals

DIP

In geology a dip is the inclination or angle at which strata slope or dip downwards into the earth. The degree of inclination or amount of the dip, which is easily measured by a special instrument, is determined by the angle which a line drawn perpendicular to the direction of the stratum makes with the horizon. The line in which such strata cut the surface is called the strike, and is always at right angles to the dip.
Research Dip