In a k-fold cross-validation, we divide the data into k groups. Are these groups called the "folds"? Can the word "fold" be used when I talk about these groups? Is it usual? Is the "fold" even a noun in this context in the statistical English?
If not, how do you call these k groups? Just "groups"?
PS: I am not a native speaker so I cannot judge it by "feeling"... I haven't found any dictionary definition of the noun "fold" that would be fitting. Anyway, I do not feel like asking this question other people than statisticians, since the English language used in statistics might be very different from the common English.