This article is from the Vampires FAQ, by BJ Kuehl bj@alpha1.csd.uwm.edu with numerous contributions by others.
There is no mutually-agreed upon newsgroup definition for "vampire."
Ask a dozen readers, and you're likely to get a dozen different answers.
However, a workable blanket definition for the various types of vampires
from legend and fiction [q.v. 2.04] might go something like this: A
vampire is a being who, in order to maintain its existence, must feed
on the vitality of humans.
Given that core definition, you're now free to qualify the terms to suit
the specific type of vampire being described. For example, the vampire
can be living, dead, undead, or spiritual. "Vitality" can mean blood,
lifeforce, passion, chi, soul, psychic/sexual energy, etc. Important to
the definition is the word "must" in that it disqualifies blood fetishers
who do not NEED blood to survive. "Feed" can be changed to "ingest",
"suck", "prey" or "drink" but, whatever term is selected, it should
disqualify flesh-eating beings such as ghouls.
A few years ago, in an attempt to add more bite to the definition, I
surveyed readers of a.v. and asked them to rate 16 characteristics as
to their perceived importance to the definition of "vampire." The most
important features of a "vampire," according to the 150+ replies I
received, are that s/he feeds on human lifeforce, does not age, is
immortal, and drinks human blood. This gives more weight to the suggested
blanket definition in which the vampire is a being who must feed on the
vitality of humans in order to survive, with the added qualifiers that,
if the need is met, the vampire is rendered unaging and long-lived. [NOTE:
The term "long-lived" is currently preferred over "immortal" because
immortality implies that one cannot cease to exist, yet there are a number
of ways that vampires can be destroyed [q.v. 2.07].
Of medium importance are that the vampire is a living corpse, is
telepathic, is harmed by the sun, feeds on human passions, and has fangs.
Of little importance is that s/he casts no reflection, loves darkness,
has a pale complexion, sleeps in a coffin, is repelled by a cross, is
prone to obsessive love, and wears a black cape.
 
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