a prefix meaning “toward,” “to,” “on,” “over,” “against,” originally occurring in loanwords from Latin, but now used also, with the sense of “reversely,” “inversely,” to form Neo-Latin and English scientific terms: object; obligate; oblanceolate.
from Old French, from Latin ob. In compound words of Latin origin, ob- (and oc-, of-, op-) indicates: to, towards (object); against (oppose); away from (obsolete); before (obstetric); down, over (obtect); for the sake of (obsecrate); and is used as an intensifier (oblong)
prefix meaning "toward, against, across, down," also used as an intensive, from Latin ob "toward, to, over against, in the way of, by reason of, about, before, in front of," from PIE root *epi, also *opi "near, against" (see epi-).
/ob/ prefix Obligatory. A piece of netiquette acknowledging that the author has been straying from the newsgroup's charter topic. For example, if a posting in alt.sex is a response to a part of someone else's posting that has nothing particularly to do with sex, the author may append "ObSex" (or "Obsex") and toss off a question or vignette about some unusual erotic act. It is considered a sign of great winnitude when one's Obs are more interesting than other people's whole postings. [Jargon File]