[Cohen]

Don't remember exactly, however:

Defence: is the skill of dodging, parrying and avoid strikes. When someone attacks you there's a confrontation beetween his attack skill and your defence (Att+2dd vs Def+2d6, rolls open ended - if a dice has rolled 6, it rolls again and adds the new number).

Protection: this is usually your armor, thick skin, or other type of magical defences.
If the attacker strikes successfully, he does some damage on the struck unit, and protection diminuish it.
(weapon damage + wielder strenght + 2d6 open) - (protection + 2d6 open).

Armor piercing weapons/spells halves the protection value.
Armor negating weapons/spells ignore protection value.

I hope I've been clear in explaining since I'm not a native english speaker, I'm Italian.