[jgranby]

If you want to be pernickety, 'alternative vote' is also a misnomer: the word 'alternative' comes from the Latin 'alter', which means 'the other of two [options]'. There are more than two voting systems, so AV is incorrect as a name, at least to traditionalists.

But this really doesn't have any bearing on which, if any, someone in Britain ought to vote for. That the name doesn't really fit doesn't say much at all about the merits of the system itself.