Urban Dictionary has several definitions of the word "Twihard" they all seem to get the point across. This is going to be known as the age of the Twihard, sadly.
Here are some definitions.
Twihard:
Hardcore fan of the Twilight series by Stephanie Meyer.
Loved the books before there was even going to be a film, and did not jump on the bandwagon because the actors were sexy(If you did this then SHAME on you).
Twihards usually have at least 3 movie posters, either have lost count of how many times they've read the book or keep a running count, and frequently quote the books in serious situations... and then get glared at by the people around them =P.
The best breed of fangirl. ;)
NOTE: Just because you've done the three examples doesn't automatically make you a twihard.=D
Girl: Hey, want some popcorn?
Twihard: 'You brought a snack?'xD
-Random Situation In Which Feathers Are Thrown (Oh It's Happened)-
Twihard- 'Why Am I Covered In Feathers
Twihard-A combination of the words "Twilight' and "Die-Hard", Twihards (usually young females) are obsessive fans of the "Twilight Saga" series of books by author Stephenie Meyer, and the film adaptations. Twihards embrace all things Twilight with religious zeal, daily visiting fansites, quoting dialoge from the series, and stalking (online or in person) the films' stars, especially on the Vancouver BC movie set. Most Twihards are "Team Edward", although the self-declared sub-category "Team Jacob" also qualifies for the Twihard designation. Comment or remark to a Twihard, and she can relate it to Twilight instantly.
Overheard conversation between two Twihards; "Only 84 days, 25 min. & 32 seconds til the next Twilight movie comes out!" Squeee!
The difference between being a Twilighter and being a Twihard, is that Twihards have embraced a new Twiligion... er.... I mean, religion based on Twilight. They live and breath Twilight. Most Twihards are for Edward and Bella. Therefore, those Twihards are all for true love & love at first sight. Point out one thing to a Twihard, and they can relate it to Twilight instantly. Savage and wild, they need every single thing to be perfect in the upcoming Twilight movie.