"What is your definition of "Undead"? Wikipedia says"
I can pretty much stop you there. As Wikipedia also includes videogames and popular beliefs in there as well and won't tell you which is which.
Ghosts are undead because they are dead, or come from a being that is dead, yet behave as if alive-- eg, they move around, think, talk, etc
No ghosts arn't dead because they are disembodied spirits within a scientific reasoning. Spirits were never living. Though it depends if you segregate body and soul but they seem to only become undead due to the fact that being undead is identified with the ghost.
Liches are undead because they have killed themselves
Wait what? They never did that... OHHH I see your using Dungeons and Dragons.
Liches don't need to have ever been dead.
Well, "they" being who exactly? Europeans? Most of Mesoamerica was still using obsidian as their material of choice for anything with an edge, and had large-scale economies and manufacturing centers based on it
Stop using Unrelated information (or at least stop using information that doesn't argue against my point). My point was that some people were using Obsideon's sharpness as a reason to give the Scapal unrealistically large advantages in the area of surgery when in fact for the most part it wouldn't make too much of a difference when compared to well constructed metalic instruments. (It was also cheaper then Gemstone instruments)
How much greater do you believe Obsideon to be? 10 times? 20 times? Obsideon scapal is an edge not a league.
I will agree that a flesh golem is not an undead, however, in that a golem is by definition a newly created form of life. LIFE. So it isn't dead. You could, on the other hand, have an undead flesh golem if the original flesh golem is killed
It really depends. Resurection doesn't make you undead. We need to seperate the idea of comming back to life and being undead. (which is easy in Dwarf Fortress because being a Zombie is a Curse and "undead" status doesn't actually exist)