What exactly is a startup?

I have changed my mind about what an orthopedic startup is.
We all casually toss the word "startup" around without any regard to what it really means.

"My friend went to a startup"
"I want to work for a startup."
"Did you hear about the new startup?"

Talk to 10 people and you may get 10 different definitions of a startup.  Probably the most common definition is a company in the first stages of operations.
Since I talk with orthopedic professionals every day, I have run into a three specific definitions for "a startup".  Let me share these three with you.
#1 - T...