チャオ

Treccani's Vocabolario derives Italian ciao from Venetian s-ciao or s-ciavo, meaning “servant” or “slave,” related to Italian schiavo. In older northern Italian usage, the phrase worked as a polite greeting formula. Modern Italian ciao is used both when meeting someone and when leaving someone. Japanese dictionaries such as Digital Daijisen and Seisenban Nihon Kokugo Daijiten list チャオ directly from Italian ciao. This is a modern katakana greeting, not a Meiji science term or an English loan. It sits near other Italian-style words in Japanese pop culture, such as ボンジョルノ, グラッチェ, and アリベデルチ, but チャオ became much easier to use in casual speech. In present-day Japanese, チャオ is a light greeting for close contact, and many speakers use it more as a goodbye than as a hello. English ciao also exists, but English dictionaries often mark it as informal and strongly associate it with parting. Italian keeps both sides active. Example: じゃあ、チャオ.