What make a camera a pro camera?

[Larry Cook]

I was reading through some posts on one of the Pentax forums that I 
follow and ran across a remark about Pentax not making any "Pro" 
cameras. At the time I thought to myself, "OK, I'm not a pro, so what? I 
like what I have, a *istD, so what the hey?!?" Then I began thinking 
(always a problem when you aren't used to doing a thing...) about it and 
I found myself wondering, What makes a camera a "Pro" camera? Is it the 
construction? Particular features? The lenses? Accessories? The people 
that use them? The mythos associated with a camera? The price? The label 
the manufacturer applies? So, how does one distinguish a pro camera from 
a non-pro camera? The amount the camera charges for its services????

Just thought I would ask and it is a serious question, more or less. It 
is serious in that I am curious. It is not that serious in that nothing 
important hinges on the answer....

Larry Cook