Free as in Speech

There's a lot of terms in the world of software that can sound like the same thing to someone not well versed in all of this.  And a lot of these terms have a lot more in common than they have different. adding to the confusion.  So exactly what is Open Source Software (OSS), Free Software, Freeware, Free and Open Source Software (FOSS) or even Shared Source Software? And more importantly, how...