In terminology, death is a defunct scientific term (see: defunct theory of life), of religio-mythology origin, formerly defined as the termination of life, conceptualized to refer to a "special" end state (see: life principle) of conatus-like existence of powered animated motile carbon-based or CHNOPS-plus based matter. 
Life terminology upgrades
See main: Life terminology upgradesAs "chemistry does not know the word life" (see: defunct theory of life), as English physiologist Charles Sherrington aptly put it in 1938, so to does chemistry not recognize the word "death". In this sense, in respect to post 2010 Hmolpedia and 2012 JHT terminology reform initiatives, a few water-testing stage death-upgrade chemical thermodynamically neutral terms that have been used include:
● Died → Dereacted (Ѻ) ; Deboundstated
● Dead → Debounded; No reaction existence
● Death → Reaction end
Though, to note, it is difficult to find actual historical precedence in respect to reform of this specific term.
In 1944, American anthropologist Alfred Kroeber defined the death of a society or cultural “dying”, in what seem to be physical chemistry terms, as follows: 
“Cultural dying is a replacement of most of the material and patterns with new material and patterns developed within the culture, until after a sufficient length of time, the transformation is so great that it is descriptively more useful to speak of the end product as a new culture, or one different from the original one.”
This is an intuitive view being that what are perceptually conceived as "biological entities", such as birds and bees, are actually carbon-centric reactive molecules, formed through chemical reaction synthesis, and transformed likewise in a reverse type of reaction, but do not actually "live" or "die", in a physical chemistry sense.
In the 1850s, Scottish physicist William Thomson and German physicist Rudolf Clausius proposed the "heat death" end state model of the universe. 
In 1944, Austrian physicist physicist Erwin Schrödinger defined death, thermodynamically, as "the dangerous state of maximum entropy".  The study of what happens to a person when they die, according to the laws of thermodynamics, is called cessation thermodynamics. 
Author Stephen Haines, an engineer, management consultant, and human systems theorist, states, based on extrapolations of the heat death theory, that entropy refers to the natural characteristic of all living systems to eventually slow down and die. 
The following are popular death quotes:
“There is neither birth nor death for any mortal, but only a combination and separation of that which was combined, and this is what amongst laymen they call ‘birth’ and ‘death’. Only infants or short-sighted persons imagine any thing is ‘born’ which did not exist before, or that any thing can ‘die’ or parish totally.”
— Empedocles (c.450BC) fragment; cited by Baron d’Holbach in The System of Nature (pg. 27); cited by cited by Alfred Lotka (1925) in Elements of Physical Biology (pg. 185, 246)
“Death is a punishment to some, to some a gift, and to many a favor.”
— Seneca (c.55AD) (Ѻ)
“Sleep is lovely, death is better still, not to have been born is of course the miracle.”
— Heinrich Heine (c.1835) (Ѻ)
“Death is a stripping away of all that is not you. The secret of life is to die before you die—and find that there is no death.”
— Eckhart Tolle (1997), The Power of Now (Ѻ) 
1. Death (definition) - Merriam-Webster's Collegiate Dictionary (2000), CD-Rom, version 2.5.
2. Schrödinger, Erwin. (1944). What is Life? (ch. 6 “Order, Disorder, and Entropy). pgs. 67-75 Cambridge: Cambridge University Press.
3. Thomson, William. (1862). “On the age of the sun’s heat”, Macmillan’s Mag., 5, 288-93; PL, 1, 394-68.
4. Thims, Libb. (2007). Human Chemistry (Volume Two) (preview), Ch 16: section "Cessation Thermodynamics", (693-699). Morrisville, NC: LuLu.
5. Haines, Stephen G. (2000). The Complete Guide to Systems Thinking and Learning (pg. 19). HRD Press.
6. (a) Kroeber, Alfred L. (1944). Configurations of Culture Growth (pg. 820). University of California Press.
(b) Wallace, Thomas P. (2009). Wealth, Energy, and Human Values: the Dynamics of Decaying Civilizations from Ancient Greece to America (pg. 231). AuthorHouse.
7. (a) Tolle, Eckhart. (1997). The Power of Now (“no death”, pgs. 46, 223). New World Library, 2010.
(b) The Power of Now – Wikipedia.
● Death – Wikipedia.