My last posting made an opportunist reference to the cinematic flavor du jour, New Moon, the latest in the made-for-sequels Twilight series. I use the word opportunistic because I am fully aware that I am shamelessly exploiting the current pop culture zeitgeist to snag (or is that snare) hapless web surfers and drag them to this site.
The current cultural vogue for sparring between vampires and werewolves is, for me, much better covered in the movie, Underworld, with Kate Beckinsale proving that female vampires can be just as erotic as male ones, and Bill Nighy turning in a splendidly entertaining performance as Viktor, the 1500-year-old vampire elder.
So having dealt with the etymology of vampire, it seems only fair to bite into werewolf and the plural, werewolves. And we can start with the definition offered by the OED:
A person who (according to mediæval superstition) was transformed or was capable of transforming himself at times into a wolf. (obsolete) also, an exceptionally large and ferocious wolf. (OED, Vol.XX, p.158)
The first written definition of a werewolf in the English comes from Richard Verstegan‘s A restitution of decayed intelligence: in antiquities (1605) where we see;
The were-wolues are certaine sorcerers, who hauing annoynted their bodyes, with an oyntment which they make by the instinct of the deuil; and putting on a certaine inchanted girdel, do not only vnto the view of othres seems as wolues, but to their own thinking haue both the shape and nature of wolues, so long as they weare the said girdel.
The word itself is found as the Old English werewulf, which is thought by most to have been formed from the Old English wer meaning “man” and wulf meaning “wolf.” The latter is a found in many of the Germanic languages as ulfr (Old Norse); wolf (Old Frisian, Old High German); and wulf (Old Saxon).
In Greek, the word for wolf is λύκος, which forms the basis for the other common word for werewolfery (or werewolfism) – lycanthropy. The word for “man” in Greek is ανθρωπος or anthropos, where we also get such words as anthropology, the study of mankind. Note that anthropos refers to humans, not just the sexual gender of “man” as opposed to “woman,” and lycanthropes can be both male and female.
The original werewolf is arguably the Greek king of ancient Arcadia called Lycaon. A thoroughly wicked king, Zeus decided to test him to see if he had any redeeming qualities whatsoever and after taking the form of a man, he made his way to Lycaon’s palace. There, in a reversal of roles, Lycaon decided to put Zeus to the test to see if he would eat human flesh. While relating the story of his encounter with the Arcadian king to his fellow gods, Zeus said of Lycaon that;
a hostage sent by the Molossians,
and after severing his windpipe, cut
his body into pieces and then put
the throbbing parts up to be boiled or broiled.” 
Yummy! Of course, Zeus refused to eat the Molossian snack and instead set about tossing thunderbolts across the land, killing all of Lycaon’s fifty sons and turning the king himself into a wolf:
“His garments now become a shaggy pelt;
his arms turn into legs, and he, to wolf
while still retaining traces of the man:
greyness the same; the same cruel visage
the same cold eyes and bestial appearance.” 
In a further fit of pique, Zeus followed up by causing a flood that destroyed the world, except for the virtuous couple, Deucalion and Pyrrha, who managed to build a boat and survive.
Anyhow, if you’re wanting to score points at the office party this year, while simultaneously trying to look hip, cool, and “in the moment” as regards popular culture, you might want to casual mention that in old Scottish dialect, a werewolf was something very different from the usual 500 lbs of fur, claws, and teeth with a penchant for ripping out throats. In the 1808 An etymological dictionary of the Scottish language, John Jamieson defines a warwolf as “a puny child or an ill-grown person of whatever age; pronounced warwoof.”
And one other quirky definition relates to the an attempt by the Nazis at the end of World War II to create an underground paramilitary group that would continue the fight. The group was conceived by Heinrich Himmler, the head of the SS, who initiated Operation Werewolf (Unternehmen Werwolf) with the aim of having small groups of elite forces wreak havoc as guerrilla fighters behind enemy lines. Although nothing came of this, except a few alleged actions that have since been disputed due to lack of evidence, it’s a great story to use to impress your hosts.
As with modern vampires, werewolves have assumed a romantic semi-heroic status, being seen more as naughty puppies who need a cuddle rather than a solid silver slug through the head.