In
Dungeons & Dragons' third edition
Player's Handbook, Two-Weapon Fighting is described as a
feat (special ability) that your
player character (or "PC") can acquire. From the
Player's Handbook (p.86):
"You can fight with a weapon in each hand. You can make one extra attack each round with the second weapon.
One of the better feats for PCs who want to
kick ass, although it is almost
worthless without
Ambidexterity -- the
penalties for two-weapon fighting are typically so high that it's almost not worth it.