https://en.wikipedia.org/wiki/Figure_drawing
Interesting post though. I liked seeing the Cowboy Bebop characters again, and the point about the need for the body to be identifiable without clothes makes a lot of sense.
Edit: memory failure (just woke up, I guess it counts as an excuse) The book is /Gesture/ drawing for animation, not figure drawing. I mentally mixed the article content with your reference :) The book is great, though.
My experience has always been that "figure drawing" refers to sitting down in front of a live model, probably a naked one, and drawing them. You'll see people referring to drawing from pictures of naked people as figure drawing as well.
Diaz only uses the term once, at the beginning of this article:
"Figure drawing is a pivotal tool to any artist, but being able to effectively render humans and creatures is only part of the equation. Even if your draftsmanship is solid, you won’t get far if your designs are uninteresting."
By this, I think he is saying "it is very very important to be able to draw models from life and to know a ton of anatomy - but that's not what I'm here to talk about. I'm here to talk about character design." Which he then proceeds to do for the remainder of the article. (And I will strongly agree that a good foundation in life drawing will serve any cartoonist well, no matter how stylized their work is!)
In my experience, the most common usage of the term "figure drawing" in the fields of comics and animation is "man I'm getting rusty, I really should get some figure drawing in again but I am so BUSY."