"arched roof or ceiling," c.1300, vaute, from O.Fr. voute "arch, vaulted roof," from V.L. *volta, contraction of *volvita, noun use of fem. of *volvitus, alteration of L. volutus "bowed, arched," pp. of volvere "to turn, turn around, roll" (see vulva). The -l- appeared in Eng. c.1400.
vault
"jump or leap over," 1531 (implied in vaulting), from M.Fr. volter "to gambol, leap," from It. voltare "to turn," from V.L. *volvitare "to turn, leap," frequentative of L. volvere "to turn, turn around, roll" (see vulva).