iteration
noun [ C or U ] uk/ˌɪt.ərˈeɪ.ʃən/ us/ˌɪt̬.əˈreɪ.ʃən/
formal反复（通常为了作出改善而重复做某事）
the process of doing something again and again, usually to improve it, or one of the times you do it
the repetition and iteration that goes on in designing something 在设计某物时的重复与反复修改
The software is on its fifth iteration. 这个软件已经是第五版。
mathematics, computing specialized迭代，叠代（数学里若干次使用一个数学法则得出的量）
an amount that you get when you use a mathematical rule several times