What does 'Int'l Ed' stand for? We say that you would like to buy either

Principles of Mathematical Analysis (Int'l Ed)


or
Principles of Mathematical Analysis.


Principles of Mathematical Analysis (Int'l Ed) costs nearly half as much as Principles of Mathematical Analysis. 

I know that Int'l Ed stands for international edition. But what does (Int'l Ed) stand for, more than just international edition, e.g. what does the Int'l label mean to to the text and content in the book? It just drives me nuts! I have a really hard time finding an answer by simply searching the web, so I ask the question here. 

What are the differences between two books, or any two books - one book labeled Int'l Ed and the other book not?
My first thought was "international education" but then seeing the context, it is clearly "international edition".
My first thought was "international education" but then seeing the context, it is clearly "international edition".