Armor

Armor consists of any covering or garment designed to protect the wearer from injury in Combat. It is generally constructed from leather or metal and can take a number of different forms, offering various levels of protection (see https://roll20.net/compendium/dnd5e/Armor#content, but note the variant rules detailed below). Various Races in The Old World have produced Armor throughout history, often driving the development of new weapons in order to counter it. During the Age of Reckoning, for example, the development of heavy plate Armor rendered knights and other elite warriors nearly invulnerable until the invention of Firearms. In the modern era, Armor no longer plays a dominant role on the battlefield, but remains relatively common, particularly among Adventurers.

Characters who choose to wear Armor are subject to the following variant rules: 
When a character who is wearing heavy Armor and is proficient with that Armor takes bludgeoning, piercing, or slashing damage from a weapon which is not magical and does not have the Penetrating quality, they reduce that damage by an amount equal to their Proficiency Bonus; A character who is wearing medium Armor and is proficient with that Armor reduces damage in the same fashion by an amount equal to half their Proficiency Bonus, rounded down.