I know I am going to feel stupid as soon as someone answers this, but what the heck does "gish" mean? I see it all over and I just can't figure it out.
As Baka stated above, it originated from the Githyanki, but the term has since been used to describe ANY martial/caster class such as an Eldritch Knight, Magus, or Feral Alchemist. It's kind like how we call all facial tissue "Kleenex" even though that is a trademarked name, and not a general description.
Tashen - I'm glad you asked. I had read the term a few times, but ran across it quite a bit today, and now I know what it means.