Parental alienation is the creation of a singular relationship between a child and one parent, to the exclusion of the other parent. The fully alienated child is a child who does not wish to have any contact whatsoever with one parent and who expresses only negative feelings for that parent and only positive feelings for the other parent. This child has lost the range of feelings for both parents that is normal for any child.

There are significant disputes between the experts as to the theoretical framework for this phenomenon and as to the appropriate terminology to apply to understand it, which disputes are beyond the scope of this article. We have tried to adopt language with common sense meaning for our discussion and use the term "alienation" in its non-technical sense.

We also call the parent who acts to create such a singular relationship between the child and himself the "alienating parent". The parent who is excluded from the singular relationship is "the target parent".