'巴士' is a phonetic loanword from English 'bus', adopted into Mandarin to refer specifically to motorized public transport vehicles that carry passengers along fixed routes. Though the characters 巴 and 士 individually mean 'to long for' and 'scholar/gentleman' respectively, their combination here carries no semantic relationship to those meanings — they are used purely for sound (bā shì ≈ 'bus'). This makes 巴士 a classic example of transliteration in Chinese, where pronunciation takes priority over meaning.

The term is widely used across mainland China, Hong Kong, and Malaysia, especially in informal and everyday speech. It's more common than the native term 公交车 (gōng jiāo chē) in southern regions and among younger speakers. While not formal in academic or official documents, 巴士 appears frequently on signs, apps, and casual conversation — for instance, when asking for directions or checking schedules. It’s rarely used in compound words beyond basic phrases like '巴士站' (bus stop) or '双层巴士' (double-decker bus).