小组 (xiǎo zǔ) literally means 'small group' — 小 (xiǎo) means 'small' or 'little', and 组 (zǔ) means 'group', 'team', or 'set'. Together, they refer to a small, purpose-driven subgroup formed within a larger organization, class, or activity. It emphasizes size and function: not just any collection of people, but a coordinated unit with shared tasks or goals.

This term is widely used in educational, workplace, and community settings — for example, students forming study groups, office colleagues collaborating on a project, or volunteers organizing an event. Unlike more formal terms like 部门 (bùmén, 'department') or more casual ones like 一伙人 (yī huǒ rén, 'a bunch of people'), 小组 carries neutral-to-positive connotations of cooperation, manageability, and shared responsibility. It’s common in both spoken and written Mandarin and rarely used for animals or inanimate objects.