Size
Light
Damage is rolled with disfavor unless thrown. During a grapple, damage is rolled with favor. Two light weapons occupy one slot. Can be wielded in the off hand.
Short
One handed. Occupies one slot. Can be wielded in the off hand.
Medium
One handed. Occupies one slot.
Long
Attacks have a longer range. You get a free attack on enemies as they enter range. Two handed, bulky.
Great
Damage is rolled with favor. Two handed, bulky.