‘上诉’ is a formal legal verb meaning 'to appeal (a court decision) to a higher judicial authority.' It combines two characters: 上 (shàng), meaning 'up' or 'to a higher level,' and 诉 (sù), meaning 'to file a complaint' or 'to litigate.' Together, they literally convey the idea of taking a case 'upward' in the court hierarchy to seek review or reversal of a lower court's ruling. This term is used exclusively in legal contexts and implies adherence to strict procedural rules and deadlines.

The word appears in official documents, news reports about court cases, and courtroom discussions. It is never used for informal complaints or everyday grievances — those would use words like 抱怨 (bào yuàn) or 投诉 (tóu sù). '上诉' always refers to a structured, rights-based challenge within China’s judicial system, and the appellant must have standing and valid legal grounds, such as errors in law or procedure.