Agraph that has a finite or limited number of data points is a discrete graph. a qualitative graph. a continuous graph. a cosmograph.

discrete number or values, are numbers that are unbreakable, and therefore the data is represented in a graph by data points that are limited in nature in the extent that there can't be a value in between, so that'd make it a discrete graph.

a good example on discrete values is say, you have two cars, and each car can take 5 people, and you want to drive about 9 people, how many can you fit in the car?

well 9÷2 = 4.5, that means you can put 4.5 people in each car.

now, how are we going to to do that?  put 4 in and then saw one off in half?

so you see, the 9 value is discrete, you can't have half or a fraction of a person, is either a whole person or not.