Preliminary ruling
A preliminary ruling is not a concrete verdict. It is an interpretation by the EU Court of the EU rules needed for a concrete verdict in a member state.
The EU Court in Luxembourg may be asked to give a preliminary ruling on a point of EU law that is referred to it by a Court of one of its member states.
Member states have no right to have their own interpretations of EU law and are obliged to ask the EU Court when the national courts are in doubt on the content of EU law.
Preliminary rulings influence the development of EU law at the supra-national level, even though the case in question is not before the EU Court.