You already know anime and manga from above. Here are some other, re-occuring words and phrases you'll come across while watching anime or talking about it with friends.

Baka!

"You're stupid!"

chara

character

chibi

Short, tiny. A chibi character may naturally resemble a super-deformed character, where the entire body has a smaller, squashed, cuter appearance.

dojinshi

Generally fan stories pertaining to a specific series. Could also be any series specific fan art.

hentai

Abnormality. Sexual perversion. Used also to describe a certain class of anime, manga or otaku (as in "H-Anime").

idol

(a) Certain people and characters transcend being something that you're a fan of. When you start worshipping them, adorning yourself in their image, collecting dolls, images or cards of the character, they've become your idol. (b) Singers with a major role in a series (Minmei from Macross for example).