Iterate is a verb meaning to say or perform again. Iteration is a noun meaning the act or instance of iterating. It is synonymous with repetition, but iterations usually work toward a perfect form of something. Writers often mistakenly use iteration to mean instance or version even when there is no repetition—for example:
Ranch, in its low-fat iteration, is also touted as a viable part of a healthful school lunch … [Washington Post]
Later versions left out the flour entirely, making a truly flourless iteration. [New York Times]
In one iteration of the film, its budget hovered around $70 million … [Los Angeles Times]
In these examples, iteration is correct because it implies repetition:
The annual event, now in its 135th iteration, includes more than 2,500 animals across 179 breeds. [Salon]
The company will also launch the fifth iteration of its popular iPhone as rivals from Motorola Mobility to Samsung Electronics apply pressure. [Reuters]
Iterations help establish the cadence of work. [Forbes]
The first version of something can’t be an iteration. The word only applies to the repetitions. The second iteration of something would technically be the third version, the third iteration the fourth version, and so on—but no one bothers with this minor logical point.
Incidentally, reiteration should probably be considered redundant, but it’s so entrenched in the language that there’s no sense in opposing it.
