This is a thread that's mainly for talking about what anime term means what, though talk about anything anime is welcomed.
Some of the terms I know:
Hentai: Naughty stuff where if you watch it, a random neko cat girl with pink hair will fall out of the sky on top of you and gouge your eyes out with a hammer that they pull out of no where.
Harem: This is an anime where the main protagonist is usually a guy (but ones with a girl as the main protagonist are known) where a bunch of girls (guys if the protagonist is a girl), at least 4, all fall in love with the protagonist. On the last episode, the protagonist will choose one and everyone else will curl up in a ball near the closest corner and cry... or kill the protaganist... most common of all, though, is everyone else going "WAAAAA?!" and then just being friends with the main protagonist.
Shonen: This is an anime created mainly for guys.
We don't have time to do things right the first time. But we have time go back and do it again. Why not do it right the first ti