DIP (AS. dyppan, dippan, to dip, Goth, daupjan, OHG. toufen, Ger. taufen, to baptize, from AS. dēop, Icel. djūpr, Goth, diups, OHG. tiof, Ger. tief, Engl. deep). A term used by geologists to denote the inclination of rocks to a horizontal plane. Stratified and schistose rocks are seldom horizontal, and their dip may vary from a slight inclination to absolute verticality. The amount of dip (expressed in degrees) is measured by a clinometer (q.v.). When strata have been upraised into dome-shaped structures which have an outward slope in every direction from a central point the dip is called ‘quâ-quâ-versal.’