What does to be held in Contempt mean for violating a court order?

Contempt of court is a court ruling which, in the context of a court trial or hearing, deems an individual as holding contempt for the court, its process, and its invested powers. Often stated simply as "in contempt," or a person "held in contempt," it is the highest remedy of a judge to impose sanctions on an individual for acts which excessively or in a wanton manner disrupt the normal process of a court hearing.

From:

Contempt of court - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/Contempt_of_court)

Basically it means you have defied a valid order of a court of law and the judge of that court can impose sanctions against you. Such sanctions can include fines or jail time.

Exactly what it says. If you have a court order for something and don't comply with it, that's contempt. Failure to pay child support is a common instance of contempt. Violating a restraining order is another one.