Darwin did not define the term “natural selection” in the “GLOSSARY OF THE PRINCIPAL SCIENTIFIC TERMS” in The Origin of Species.

To illustrate the actions of “natural selection,” Darwin developed “imaginary illustrations”:

In order to make it clear how, as I believe, natural selection acts, I must beg permission to give one or two imaginary illustrations.

Since evolutionary scientists are unable to define “natural selection”, the existence of the term as a natural law is now in question:

Conrad H Waddington

There, you do come to what is, in effect, a vacuous statement: Natural selection is that some things leave more offspring than others; and you ask, which leave more offspring than others; and it is those that leave more offspring; and there is nothing more to it than that.

Jerry Fodor and Massimo Palmarini

We have both spent effort and ink… to show that Darwin’s theory of natural selection is fatally flawed.

Giuseppe Sermonti

Natural selection could perhaps be invoked as a mechanism accounting for the survival of the species. But the claim that natural selection is creative of life…  can only leave one dumbstruck.