The High Court is the highest Australian court. Appeals may be made to it from the state Supreme Courts, the Federal Court and the Family Court. Some matters, such as constitutional matters, may go directly to it. The High Court sits permanently in Canberra, but visits the various State capitals from time to time to hear appeals.
High Court decisions are binding on all States and so its decision on a case appealed from, say, the Victorian Supreme Court to the High Court will usually be binding on all other State courts should the same question arise there.
The High Court does not automatically hear every appeal made to it. Before the High Court hears an appeal it conducts a short hearing (called an 'Application for Special Leave to Appeal') to decide whether there is a legal issue which would justify a grant of special leave.