Pureblood?

[heidi]

No: HPFGUIDX 2832

I've been wondering about a definition in the wizarding world - one
which we've talked about before.
I know there is no definite answer to this, but I am wondering what
y'all think.
Is someone only pureblood if their ancestors are only witches & wizards,
or are they pureblood if their ancestors are only Of Magical Blood?
In other words,clearly, someone who has at least 9 generations of
witches & wizards as ancestors would be a pureblood (say, in the
definition used by Ernie MacMillan).
But what about someone who has, say, a Veela as a grandmother, like
Fleur? Is she a pureblood?
Also, in Cassandra's Draco Sinister (the sequel to Draco Dormiens),
Draco says that one of his ancestors is a veela as well - which means
either that Lucius is descended from a veela, or at least married & had
a child with someone who was. Given the big exception of VOldemort being
half-muggle-born, how well would something like that go over at the
Tuesday Night Death Eater meetings?
And if it just has to be a magical creature, then what would the status
be of someone who was half wizard, half house elf (if such a thing were
genetically possible (but if giant/wizard or giant/witch pairings are,
why not?))?