Member variable,class variable and instance variable

Instance variable: -A field declared without the static modifier is called an instance variable. An instance variable of a class comes into existence when a new instance of that class is created, and ceases to exist when there are no references to that instance and the instance's finalize (if any) has executed.

Field: -A field is a variable of any type that is declared directly in a class or struct. Fields are members of their containing type.

http://msdn.microsoft.com/en-us/library/ms173118.aspx

http://www.csharpuniversity.com/2008/10/14/class-variables-member-variables-and-instance-variables/

Reference type variables are named appropriately (reference) because the variable holds a reference to an object. In C and C++, you have something similar that is called a pointer, which points to an object. While you can modify a pointer, you can't modify the value of a reference - it simply points at the object in memory.