Deliverability versus delivery

Deliverability is a term so many people use every day, but what do we really mean when we use it? Is there an accepted definition of deliverability? Is the concept different than delivery?
At a recent conference I was running a session talking about email delivery, senders and the roles senders play in the email industry and at that particular organization. The discussion went on for a while, and the subject of deliverability versus delivery came up. J.D. Falk had a comment about the difference that resonated with me. Paraphrased, he said:

Delivery is what happens to a particular email. It is what ISPs are most concerned about.
Deliverability is the delivery potential of a particular email. It is what marketers, commercial senders and ESPs are concerned about. Deliverability is more than just “can this email be delivered”, it is the sum total of factors that play into email marketing: relevance, structure, content, and reputation.

This was such an insightful comment. I can help clients improve their deliverability, but only if they’re willing to make some changes to what they’re doing. Deliverability not just telling the ISPs that the mail is good and that it should be accepted, but is more about sending mail that recipients want and that they will tell the ISPs they want.
When thinking about deliverability improvements you can make, remember that deliverabilty is not just the email, but the whole process from address acquisition through purchase.