2. A squealing sound. Can be either happy or scared (in Squee's case, it's scared.)
3. A creature in a game called Myst III. (I don't know much about this kind of squee. I've seen pictures of them, before. They look kind of rodentish.)
2. "Squeeeee! Can you believe it? I won!" -someone who just won a contest and feels overjoyed
3. "I bought a squee plushie over the internet. They look so cute and cuddly!" -someone who bought a plushie of the rodentlike creature in Myst III
noun: A feeling of excitement and happiness, such that one feels like squeeing
You wouldn't believe how full of squee I am right now.