cusping,n.Arch.|ˈkʌspɪŋ| [f. cusp + -ing: cf.coving, roofing, etc.] A formation consisting of cusps; cusp-work. 1860G. E. Street in Archæol. Cant. III. 124 The cusping was let into a groove.1870F. R. Wilson Ch. Lindisf. 101 It has five lights, the cuspings of which..are early.