习俗 (xí sú) means 'custom' or 'tradition'—a long-established practice shared by a group, often passed down through generations. The first character 习 (xí) means 'to practice' or 'to become accustomed to,' while 俗 (sú) means 'common,' 'popular,' or 'folk.' Together, they convey the idea of practices that people have repeatedly adopted and accepted as part of their communal life.

This word is commonly used when discussing cultural behaviors tied to festivals, family life, or regional identity—such as lunar new year customs, wedding rituals, or local holiday observances. It carries a neutral-to-positive connotation and implies social continuity rather than mere habit. Unlike the more formal term 传统 (chuán tǒng), 习俗 emphasizes observable, everyday practices rather than abstract heritage or ideological values.