Armors
Armors are just like weapons only used for defense and helps your AC value! Armors are worn naturally if your type of character can wield it! Armor upgrades are also in 1+s, 2+s, and 3+s! I should add, the AC system is weird. The better defense you have, the LOWER your AC goes! This may be a bug, I'm not sure, but anyway, that's the truth, your AC LOWERS, so I'm to presume it means it grows higher.

Leather
Armor-AC 2-Leather Armor is what Armor Shops first sell, despite the
Chain Mail 1+ hidden in the south east Crypt in town, this is what your
Fighters/Elves/Dwarves should equip!
Chain
Mail-AC 4- Ah yes, CHAIN MAIL becomes available a bit later in the
game! A very nice AC compared to Leather Armor, definitely worth buying!
Shield-AC
1- Shields are very nice actually due to it being an extra point of
AC! Definitely should get for those who can use it.
It's a pity D&D never possessed Mage/Thief type of gear such as Robes and such! Oh well!