Ordinal is the type of variables, which normally come in form of set of values that have the meaning in their orders. So they are available to make comparison of their orders but unavailable to do the addition computation or any arithmetic. They can come in form of both numeric and string. However, the interval between them is not necessarily equal.
Sample 1 : Monday, Tuesday, Wednesday, etc.
Sample 2 : January, February, March, etc.
Sample 3 : Y1999, Y2000, Y2001, Y2002, etc.
Sample 4 : 1st , 2nd , 3rd , 4th , etc.
Sample 5 : Low, Medium, High
Sample 6 : Millimeter, Centimeter, Decimeter, Meter, etc.
Sample 7 : Primary School, Secondary School, High School, University
[Nata AIT, 2006]