According to the New Oxford American Dictionary, death is “the end of life of a person or organism.” Wikipedia, which is never wrong, clarifies the definition even further. It states that death is “the permanent cessation of all biological functions that sustain a living organism,” then goes on to enumerate the many potential causes of death:
aging, physiological or organ failure, predation, poisoning, malnutrition, disease, suicide, homicide, asphyxia, drowning, severe burns, drug intoxication, starvation, dehydration, electrocution, intense heat or cold, radiation toxicity, warfare attacks such as bombings, as well as explosions and accidents or major trauma resulting in fatal injury
As the philosopher-poets of the band Cake so eloquently put it, “as soon as you’re born, you start dying.” Death in the CLU, as in the real world, is the end-result of life. So, to once again quote Cake, “you might as well have a good time.”
According to the journals of Ada Coffin, any person may be “brought back to life” through the use of a potion passed down to her by her foremothers. See The Unstuck for full details. But the gist is this: combining Ada’s base potion with a piece of genetic material taken from the dead individual allows for the “resurrection” of said individual.
It should be noted, however, that this “cure” for death is a carefully guarded secret at present. Only Ada Coffin (in 1892; see The Seven Wives of Silver) and Tracy Silver (in 2011; see The Boot of Destiny) are known to have successfully implemented this treatment. So, to the average mortal organism in the CLU, death remains a rather unavoidable affair.
Emily Henderson observed in the short story “Deus ex Machina” that, though she had been a “guardian angel” for a century, she had aged only 10 years in that time. This may in fact have been due to frequent visits to The Strumpet’s Sister, which is how the old landlady traveled between times and places. Since the Sister exists outside of the normal laws of time and space, it appears that individuals who stay inside that building do not age in the same way those outside do. In that way, death by aging can be prevented.
But death by cirrhosis from spending too much time inside a pub, albeit an otherworldly one, is still on the table.