族 (zú) is a suffix that attaches to a word to denote a group of people sharing a common trait — most commonly an ethnic group (汉族) or a social category (上班族). Unlike the nouns 民族 (mín zú, ethnic group) and 种族 (zhǒng zú, race), 族 is not a standalone noun; it always follows a modifier. It is also more productive, forming casual labels for lifestyle groups.