Yeah, mostly semantics. I view a SIP as more in one self contained bucket with the reservoir as part of the container, while I view a swick as a setup where the reservoir is completely separate from the grow mix, but connected by an artifical fabric wick. The reservoir can be completely outside of the container.
But the wick (usually fabric but sometimes a bed of perlite) as the link who's sole function is to move water, is the distinguishing feature for me.
tadaaaa
I believe this to be the best and most definitive of the explanations. I here by dub Azimuth as ruler of the sippers definition and would like to put this issue to rest and
lets get growing!!!