# Iteration vs. Repetition

What is the difference between "iteration" and "repetition"?

I have looked on wiktionary but I can't catch the difference in their semantics. Does any reference define the difference between these two words?

Wiktionary gives:

iteration (plural iterations)

1. Recital or performance a second time; repetition.

2. A variation or version.

• The architect drafted several iterations of the floorplan before deciding on his final design.
3. (computing) The use of repetition in a computer program, especially in the form of a loop.

4. (computing) A single repetition of the code within such a repetitive process. The code calculates the appropriate value at each iteration.

repetition (countable and uncountable, plural repetitions)

1. The act or an instance of repeating or being repeated.

2. (weightlifting): The act of performing a single, controlled exercise motion; also called a rep. A group of repetitions is a set.

Definitions 1, 3 and 4 for "iteration" seem to be synonymous with "repetition" (obviously definition 1 of it).

• Think of repetition as doing the same thing with the same data over and over. Think of iteration as doing the same thing with different or refined data.
– Jim
Aug 9, 2017 at 6:36
• The difference depends on context; in some contexts, there is none. Aug 9, 2017 at 7:40
• Hmm looks best answer with no significances Aug 9, 2017 at 7:41
• Not sure what you mean by that. Aug 9, 2017 at 7:44
• I am afraid that's the best I can do with such a wide question. It's up to you to provide the context. -- Note that most answers given so far assume the context is computing. Aug 9, 2017 at 7:53

Iteration uses an iterator to count through a list of (usually different) items:

Today, I must:
1: go shopping
2: clean the house
3: mow the lawn

Repetition does the same thing again, and again, etc...:

One sheep, two sheep, three sheep, ...

• So you mean iteration := {alterate, list, traverse} repeat := {same, do, again} Aug 9, 2017 at 7:25
• I am using iterator protocols as a guide and the fact that repetition is a kind of simplified iteration. Your version sounds about right.
– JMP
Aug 9, 2017 at 7:29
• Are you one who has an experience in nlp ? Aug 9, 2017 at 7:31
• what's nlp? if it's nlp, then: "NLP has since been overwhelmingly discredited scientifically,"
– JMP
Aug 9, 2017 at 7:36
• No I refer nlp to natual language processing Aug 9, 2017 at 7:37

"Iteration" comes from the Latin "iter" meaning "journey". Iteration is performing the same task at different places or with different circumstances as part of a longer sequence. It is not doing the exact same thing (that would be reiteration - to repeat a journey). The word "Iteration" always conveys the sense of progress, improvement, growth or change.

Repetition, on the other hand, is to perform the exact same action, with no change of circumstance. Unlike "Iteration", "Repetition" does not suggest progress or movement forwards.

Usually, you repeat doing something until a certain condition is met.

(Repeat ... until ...)

On the other hand, you iterate over all the items/elements in a given list/set.

(Iterate over ... and for each ... do ...)

Iteration is more exclusively used for Vocal or Written repetition of words or sentences, While Repetition carries a wider scope and can also be used in relation to Actions.

• Please use proper punctuation, spelling, and capitalization.
– NVZ
Aug 9, 2017 at 12:50
• @techvish81 thank you! I have been looking for this everywhere. So, would iteration be an example of necessary redundancy in writing to punctuate point (like an idiom or using an adjective) vs needlessly repetitive in a sentence? Example, here is a sentence I am debating with someone: You are a treasure and your writing is addictive crack for readers. They want to emphasize how much they couldn't put down the story so instead of just using 'addictive' or 'crack', they used both despite it being redundant. Jan 3, 2021 at 22:56

Iteration implies the recurring action includes some form of counting or countability. Repetition is more general, wherein a recurring action needn't be counted, or might be, but counting is not essential.

I'm probably biased by this question as my profession uses these terms regularly (I'm a programmer).

A repetition always starts the task at zero advancement done. An example if this would be doing the dishes.

An iteration on the other hand is something you keep adding progression to it. You start from where you left it last time. An example of this would be writing an essay.