What is the meaning of Recursive?

Drawing upon, invoking, or referring back to itself.

Having to do with an object (typically a function or formula) which is defined in terms of the object itself.

Having to do with an algorithm, program, subroutine, procedure, function, or other block of code that calls itself.

Having to do with a function which can be computed by a theoretical model of a computer in a finite amount of time.(Can we add an example for this sense?)

Having to do with a set whose characteristic function is recursive (sense 4).(Can we add an example for this sense?)

Source: wiktionary.org