whats Infused?

i finished the mission on my way to thunderhead keep and saw all my armor parts has infuse on it. What does it mean?

Infused armor reduces damage you take from the Mursaat. Attacking Mursaat in armor that hasnt been infused you will die rather quickly. Happened to me once was helping a guildie do THK mission, forgot I hadnt infused my new armor & I went 1 on 1 with a Mursaat elementalist. I instantly went to 10 pips degen on health til I died. The monk or me couldnt do anything fast enough to counter it. Luckily I carry both sets of armor with me at all times.

To complete information above- infused armor reduces damage you take from spell called Spectral Agony.

I usually goto Mineral Springs to get new sets of armour infused. It's a nice trip there. Fight along the way, cap an elite skill, see if the imps drop an IDS and get armour infused.