A bookmobile is a library on wheels: a van or bus filled with books that travels to towns, schools, or streets that do not have a library building of their own, so people can borrow books there. It is mainly an American word. In Britain people more often say mobile library, which is the same idea with a plainer name. Though actually, it is not a shop and not a delivery van for sales — you do not buy the books; you borrow them, just as you would in a quiet library room, and you bring them back. The feeling is public and kind, a little old-fashioned now that so much sits on a phone, but the vehicles still run in many places. Everyday, slightly warm English; you meet it in local news more than in novels.

圖書巡迴車；行動圖書館（是借書，不是賣書）