Ob- ::
Ob- () 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-..