You can call it whatever you want. There are no rules about how many questions it must contain to be labeled a certain way. I'm not sure where you're getting these preset notions about naming conventions.
There is no hard and fast rule either about what constitutes a quiz vs. an exam vs. a test, or how many questions or how many points or how many points per question.
A colleague I work with doesn't even refer to them as quizzes or tests, but merely 'knowledge checks'. That's partially because she gives them a chance to re-work missed questions with an explanation of how the original was wrong and what the correct answer is. They also have to cite page numbers from their textbook which contain the relevant information for the corrected versions to be accepted.
I had a chemistry teacher in high school that would give us a choice on which test version to take. Some versions had more questions than others, but all were worth the same total number of points. The versions with fewer questions were harder and more complex, yet shorter. The versions with more questions took longer, but were easier.
So, depending on how confident you were, you could take a short version with the risk of losing many, many more points on wrong answers where more than a couple of missed questions resulted in a failing grade, or the longer version where a mistake only cost you a fraction of the points, and you could miss multiple questions while still getting a passing grade.
He once even offered us a one-question exam on a particularly difficult chapter, but nobody took him up on it.
