Probate is the legal process by which property owned by a someone who is deceased has passed to his or her heirs after the death. In other words, probate is simply passing title - or, determining who gets what when someone passes away, either by looking at the will, or if none exist, then the laws of intestacy - or laws that determine the hierarchy of heirs.
Probate law is a complex field and, practically speaking, requires a lawyer's guidance.