(ōb)
A river of western Asian Russian S.F.S.R., flowing 2,500 miles NW to the Ob Gulf, an inlet of the Kara Sea 500 miles long.

1. Toward; to; facing: obvert.
2. Against; in opposition to: object, obstruct.
3. Over; upon: obliterate.
4. Completely: obdurate.
5. Inversely: obovate: prefixed to adjectives in scientific Neo–Latin and English terms. Also: o– before m, as in omit; oc- before c, as in occur; of– before ƒ, as in offend; op– before p, as in oppress. [<L ob toward, for, against]