an iteration is a step where some action is repeated again and again. in everyday life, an iteration is simply a repeated action, for example when someone says, "do i have to re"iterate" myself?". in this case, the re"iteration" is what the person said and might say again. in computer science, an iteration is one run through a block of code that is repeated multiple times. in fractal geometry, an iteration is one application of the set of rules of the fractal to create another stage of the fractal. it is also used in computer programming.