1, The full form of QUIZ is  Quiznos.

QIP Holder, LLC, doing business as Quiznos, is an American franchised fast-food restaurant brand based in Denver, Colorado, that specializes in offering toasted submarine sandwiches.

2, The full form of QUIZ is  question.

This presumably occurred because quiz was associated with question, inquisitive, or perhaps the English dialect verb quiset, “to question” (probably itself short for obsolete inquisite, “to investigate”). From this new area of meaning came the noun and verb senses all too familiar to students.