The 'emo sweater' means a lot more if it belongs to the emo boy/emo girl's girlfriend/boyfriend or best friend.
Emo sweaters can be baggy or regular fit, some are hooded.
The sweater can be worn with a shirt underneath, revealing the collar above the neckline of the sweater. This is a common look for emo boys.
See also stripey tights, stripey scarves and stripey socks-very popular alternatives to the original emo sweater.