A Homunculus (Latin for "Little Human") is an artificial human created by alchemy.  They are usually seen as enemies and villains.  They can be created if you try to resurrect a dead human, which will not work.  They can be brought back as a homunculus with the humans likeness.  In the anime series, the homunculu are named after the seven deadly sins from the bible.  Greed, Wrath, Sloth, Pride, Envy, Lust, Sloth, and Gluttony.