Shield
From EHWiki
This is about the piece of equipment, not the spell by the same name.
There are three types of shields (Bucklers, Kite Shields, and Tower Shield), each with differing stats.
Shields are notable for their ability to block attacks (physical, magic, and spirit) which can allow a player to Counter-Attack.
When a player blocks an attack, they have an increased chance of gaining shield proficiency.