No the two mean the same thing and are used interchangably.Original Animation VideoOriginal Video AnimationCorrect me if I'm wrong on the above guys. I haven't thought about that OVA/OAV stands for in a while -- I just know what they mean ;;
I originally wrote "OVA" forever, but then "OAV" began to stick for some reason...I'm not sure why I changed to OAV, either.