Traditional nomenclature is usually spoken as “Cowboys and…”
Originally did call my story Cowboys and Aliens, but the story grew into a series and many people commented on the similarity to the 2011 movie or the graphic novels of the same name.
Fortunately, I have some smart beta readers, one of my readers mentioned, why not reverse it to be Aliens and Cowboys? The premise of this series is almost the exact polar opposite of what the movies and graphic novels were about.
So that’s how the series got to be called Aliens and Cowboys.