CCP 902 allows an appeal only by a party “aggrieved” by the appealed order or judgment. Here, the watermaster appointed by the court to administer its judgment allocating water rights among claimants to the same river was not aggrieved and therefore lacked standing to appeal from a trial court order which interpreted the 60-year-old judgment allocating water rights among the parties. The watermaster’s interest was only in administrating and implementing the judgment. The watermaster served as an arm of the court and had no interest in who obtained rights to the water. Since the watermaster could recover compensation for any increased cost in administering the judgment as the trial court interpreted it, the watermaster was unaffected by the court’s interpretation of the judgment. If the watermaster believes it cannot implement the decree as interpreted, the watermaster’s remedy is to seek relief from the appointment order, not to challenge the trial court’s interpretation of the decree as to the water user’s rights.