In the Agile world the terms MVP (Minimum Viable Product) and MMF (Minimum Marketable Feature) can be quite confusing. There are those that use the terms interchangeably and there are those that reverse the terms. So what is the difference anyways? Is there a difference?
Let's start with an example:
You have a ground breaking idea for the new Facebook and your developers are busy working on the back-end. But a really important conference is just a few weeks away and you need to showcase your product before somebody else showcases something similar.
In preparation for the conference you build out a login screen with username/password fields and a submit button. Clicking on the submit button just takes you to a dashboard regardless of your credentials. So there is essentially no business logic or database fetching, just fancy graphics. This is your MVP 1.
Your dashboard displays cool looking icons but clicking on those icons provides no functionality. This is your MVP 2.
Now you have something you can demo at the conference even though it doesn't do a whole lot.
So you return from your conference and you add some login authentication as well as some dashboard functionality. Now you have an MMF:
MMF = MVP1 + MVP2 + login authentication + dashboard functionality
Essentially, an MVP is intangible to the end user while an MMF is tangible. So an MMF may consist of one or many MVPs.
There are many definitions out there that call an MVP and MMF, and correspondingly an MMF an MVP. How you choose to define it is up to you. Just be consistent.
For further information on the difference between MVP and MMF here's a good source, MVP vs. MMF - What's the Difference?.