The Collaborative International Dictionary of English v.0.48:

object-oriented \ob"ject-or"i*ent*ed\, a. (Computers)
   Using data structures called objects, which encapsulate data
   and typically are accessed by passing messages, which in turn
   may trigger internal procedures within the object which are
   invisible outside the object.
   [PJC]

The Free On-line Dictionary of Computing (17 December 2009):

object-oriented
object-orientation
OO

   1.  (OO) See object-oriented programming.  See
   also object-oriented analysis, object-oriented database,
   object-oriented design.

   2.  vector graphics.