What it is: any court matter that happens after the final judgment (decree) has been entered — for example, enforcing the decree, modifying parenting time or support, or changing some of its terms.
What this means for you: a divorce decree is not necessarily the final word forever. If your life changes — a new job, a move, remarriage — a post-decree case can update the terms. These cases are as common as the original divorce.
Common post-decree actions: a parent moves and needs the parenting schedule adjusted; a job loss triggers a support modification request; one parent stops following the plan and the other files to enforce it. None of these mean the original divorce “failed” — life moved, and the court has a process to catch up.