/ Dictionary / Index O Ob: Meaning and Definition of Find definitions for: Ob Pronunciation: (ôb, ob Russ. ôp), [key] a river in the W Russian Federation in Asia, flowing NW to the Gulf of Ob. 2500 mi. (4025 km) long. an inlet of the Arctic Ocean. ab. 500 mi. (800 km) long. OB Pronunciation: [key] obstetrical. obstetrician. obstetrics. off Broadway. opening of books. ordered back. ob- Pronunciation: [key] a prefix meaning “toward,” “to,” “on,” “over,” “against,” orig. 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. ob. Pronunciation: [key] he died; she died. incidentally. oboe. observation. O.B. Pronunciation: [key] opening of books. ordered back. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. See also: ob (Thesaurus) Oaxaca oba Related Content Daily Word Quiz: quandary Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language