Poe Physical Dmg Reduction Vs Blood Rage 2

Okay, as many have said.
Attack damage: This is the damage you'll do with your auto attacks. This is physical damage. Some abilities scale with attack damage, the numbers are in orange. (The abilities aren't always physical damage, only auto attacks!)
Ability power: This is the damage you'll do with ABILITY POWER SCALING abilities. Not all abilities scale with AP. If they scale with AP the number is in green.
Physical damage: Just means the only way to reduce it is by armor
Magic damage: Only way to reduce it is by magic resist.
Read what they say they deal to figure out what kind of damage they do.
EDIT: Okay since your match history is mostly Varus. I'll describe him in depth for you.
His Q scales with attack damage and deals physical damage. This means to increase the damage of this ability you must buy attack damage. However, if your opponent wants to reduce the damage you deal to him with it, he must buy armor. Because it does physical damage.
His W scales with ability power and deals magic damage. This means to increase the damage it does, you must buy ability power (NOT RECCOMENDED FOR VARUS!) and it does magic damage. Which just means it's going to be reduced by magic resist.
His E is the same as his Q.
His R is the same as his W.
But just be careful, some champions have more complex abilities that scale with AD and AP and deal physical. Or scale with AD and deal magical.

Poe Physical Dmg Reduction Vs Blood Rage Mean

What are the pro/cons of Ele vs Physical bow builds? Because everything is physical dmg/physical leech etc. Which is important if you like to use Blood Rage. Arctic Armor/Molten Shell cannot reduce the physical degen of Blood Rage Mind over matter cannot reduce the physical degen of Blood Rage. Basically, degen damage cannot be converted, or mitigated by on hit conversion/mitigation effects because degen does not hit.