'printing' and 'edition'

[Guest guest]

In introductory pages of books we sometimes see references to for instance

the second or third printing, or the second or a revised edition.

 

Is there a difference between a 'printing' and an 'edition' of a book?

 

If the first run of a book is reprinted without any changes, presumably that

would be called the second 'printing.' If the rerun has just a few editorial

and orthographic changes, is that considered a 'revised edition' or does it

require to be considerably revamped to qualify as a new 'edition'?