A quiz is a short series of questions with a quick result. A magazine quiz might tell a reader if "he's into you," or a pop quiz in English class will let your teacher know how far you got (or didn't get) in last night's reading.
As a verb, quiz means to ask a series of questions. A teacher might quiz his students on the material covered in lecture the day before. A mother might quiz her son as to his plans for after school. The questioning meaning of the noun and verb came into use in the mid-nineteenth century, possibly influence by words like inquisitive. Before that, quiz could refer to an odd or unconventional person, a meaning which eventually gave rise to quizzical, still in use today.