What permission is:
Permission means your potential subscriber initiated the request to sign up for your emails.
What permission is not:
I got a list of email addresses and I sent everybody a double opt-in request.
Don't take my word for it -- ask Spamhaus. "You can not simply buy a list from a 3rd party and conduct a permission pass on it, you will simply be considered to be spamming and treated as a spammer."