Definition of ob- in US English:



  • 1Denoting exposure or openness.

    1. 1.1 Expressing meeting or facing.
  • 2Denoting opposition, hostility, or resistance.

    1. 2.1 Denoting hindrance, blocking, or concealment.
  • 3Denoting extensiveness, finality, or completeness.

  • 4(in modern technical words) inversely; in a direction or manner contrary to the usual.



Ob- occurs mainly in words of Latin origin. It is also found assimilated in the following forms: oc- before c (occasion); of- before f (offend); op- before p (oppress)


From Latin ob ‘towards, against, in the way of’.