Word Origin & History
ob-prefix meaning "toward, against, across, down," also used as an intensive, from L. ob "toward, against, in the way of, about, before," from PIE base *opi- (cf. Oscan op, Gk. opi- "behind," Hittite appizzis "younger," Lith. ap- "about, near," Gk. epi "on, upon").