Primary stat

A primary stat is the deciding stat for a class' power. For casters it's usually int, increasing mana.

For any primary stat except int, half the primary stat (rounded up) is added as damage on standard melee attacks. Ex: A thief has 2 standard damage, and 4 agility (their primary stat), as well as 1 strength. The thief attacks an opponent with their dagger and hits. Their maximum non-crit damage would be agi/2+damage+strength. So with 1 strength, the thief would max out at 4/2+1+2 = 5 damage on the hit.

Note that non-friendly players (monsters) do not gain extra damage from their primary stat.