制服 (zhì fú) literally means 'to make (制) clothing (服)' — the character 制 implies regulation, standardization, or making according to set rules, while 服 means 'clothing' or 'garment'. Together, they refer to standardized clothing worn by members of a specific group to indicate identity, role, or affiliation. It is commonly used for work uniforms (e.g., police, nurses, flight attendants), school uniforms, and military attire.

Unlike casual clothes, a 制服 signals formality, institutional belonging, and often authority or service function. It’s not just about appearance: wearing one usually carries expectations of professional conduct. The word does not imply coercion (despite 制 also meaning 'to subdue'), nor is it used for costumes or fancy-dress outfits — those are called 服装 (fúzhuāng) or 戏服 (xìfú). In everyday speech, 制服 is neutral and widely understood across age groups and regions.