There are differences both major and minor between these two justice systems. On the minor level, there is different terminology in the two systems. For example, the procedure that is known as a trial in adult court is called a fact-finding hearing or an adjudication hearing in the juvenile system.
This difference in terminology points to the most important major difference between the two systems. The juvenile system is somewhat less rights-based than the adult system. The juvenile system has more of a parens patriae orientation in which the system is trying to act like a parent for the juvenile offender. Therefore, there are typically no jury trials for juveniles, just a judge trying to determine whether the juvenile has committed an offense. In addition, the juvenile system is more likely to focus on rehabilitating offenders who have been found guilty where the adult system is more likely to focus on punishment.