オートバイ

1918 is an early printed point for オートバイ: the counting-dictionary entry based on Nihon Kokugo Daijiten cites Kaitei Zoho Ya, Kore wa Benri da with Auto Bicycle and 自動自転車. The safer source form is English autobicycle or auto bicycle, an old term for a motorcycle, shortened in Japanese to オートバイ. Some modern Japanese dictionaries explain it as auto plus bicycle, while Wiktionary treats autobicycle as the actual English donor. In the Taisho period, motor vehicles entered newspaper, military, police, and hobby vocabulary. オートバイシクル was too long for daily use, so オートバイ became the practical form, next to 自動二輪車, 単車, and later スクーター. Inagaki Taruho's Hoshi o Tsukuru Hito uses オートバイ in 1922, showing that the short form had moved into literary prose, not only catalog language. Japanese road law later formalized 原動機付自転車 as a related category. The form also entered Korean as 오토바이. Modern Japanese オートバイ means a motorcycle in general, including legal classes such as 大型自動二輪 and 普通自動二輪, while バイク is the shorter casual word. Present-day English normally says motorcycle or motorbike; autobicycle is dated, and autobike is regional or uncommon. Bike alone can mean bicycle in English, but バイク in Japan often means a powered two-wheeler. Example: 父は古いオートバイを修理している.