A little while ago, a poster on Political Betting made the very good point that voters should have little difficulty understanding the AV voting system once they've heard the US name for it, "Instant Run-off Voting". I'm sure that's right, which begs the obvious question - why don't we just call it that and have done with it? Alternative Vote seems almost like a randomly chosen 'brand name' by comparison. It doesn't give a particularly accurate impression of how the system works - if anything, it implies that everyone has just the one 'alternative' vote, which confusingly is how the Supplementary Vote works, not AV. Ironically, "First Past The Post" might also be more of an apt name than Alternative Vote if it hadn't already been claimed - after all, the objective for each candidate is to get past the winning post of 50%, whereas the whole point of the system we call FPTP is that there isn't actually a defined winning post at all.
Come to think of it, a much more accurate name for our present wondrous Westminster voting system would be something like "Whichever Horse Happens To Be Ahead Whenever They All Decide To Stop Running" (or a snappy WHHTBAWTADTSR for short).