A prefix signifying to, toward, before, against, reversely, etc.; also, as a simple intensive; as in oblige, to bind to; obstacle, something standing before; object, lit., to throw against; obovate, reversely, ovate. Ob- is commonly assimilated before c, f, g, and p, to oc-, of-, og-, and op-.
Webster's Revised Unabridged Dictionary (1913), edited by Noah Porter. About
1. a russian river; flows northward to the arctic ocean [syn: ob, ob river]
2. the branch of medicine dealing with childbirth and care of the mother [syn: obstetrics, ob, tocology, midwifery]