'Tú xíng' literally combines 'tú' (meaning 'convict' or 'prisoner') and 'xíng' (meaning 'punishment' or 'penalty'), together forming a formal legal term for 'imprisonment' — a judicial sentence involving confinement in prison. It is used almost exclusively in legal, official, or news contexts, not in everyday conversation. Unlike colloquial terms like '坐牢' (zuò láo), 'tú xíng' carries a neutral, institutional tone and appears in court verdicts, legal statutes, and formal reports.

The word implies a fixed-term, non-capital penalty imposed by law, typically for crimes of medium severity. It does not refer to detention without trial, administrative custody, or life imprisonment unless explicitly modified (e.g., '无期徒刑' wúqī túxíng, 'life imprisonment'). Its usage signals formality and precision — you’ll rarely hear it in casual speech or personal narratives, but frequently encounter it in news headlines about sentencing outcomes or legal commentary.