What means "Damage"?

Hi,

what is the meaning of "Damage" (like "Damage penetrates 15% fire resistence) in the passive tree?
Is it damage only you cause or does it include minion damage as well?

In general minions will only be affected if it really states "Minions ...". "Damage penetrates ..." only affects damage you do yourself.

Differences may occur if something states that enemies take increased damage, like Flammability reducing the enemies fire resistance. This will affect the fire damage of your minions.

Also if it states Allies. Like auras or the modifiers on weapons like "Allies in your presence have increased attack speed".