I've been using "Web news reader" and "RSS Web news reader." It's not
perfect, but I think it's not bad, either. It immediately
distinguishes
it from a Usenet newsreader. And even if you don't know what a
newsreader is, you still at least get the idea that it's some kind of
application that reads news from the Web.
I try not to use the term "RSS" at all, for some the same reason I
don't
say "visit amazon.com's HTML pages". But then again, my current
description
of AmphetaDesk ("a free, cross platform, open-sourced, syndicated news
aggregator") doesn't earn bonus points for being readily understandable
("what's syndication?" "what's an aggregator?").