The title says it all really. I've heard both terms used interchangeably.
I'm assuming the DEF is the underlying framework, and xConnect is built on top of that, and it is xConnect that allows you to configure endpoints and integrations from within the Sitecore client.
Will Sitecore 8.3 be required for both, or is it just xConnect we have to wait for?
Could somebody confirm, or point me to somewhere that distinguishes the two?