Death is the termination of all biological functions essential to the functioning of the body. It may occur as the result of trauma, or the natural aging process.  

Though it is usually a natural process, occuring to all humans, death has commonly been considered an unpleasant occasion, particularly for humans, due to the to the affection for the being that has died and/or for the being that has died and/or the termination of social and familial bonds with the deceased. Other concerns include fear of death, anxiety, sorrow, grief, emotional pain or solitude.

The potential for an afterlife is of concern for humans and the possibility of reward or judgement and punishment for past sin with people of certain religions.

The word "death" has two meanings to Christians.  First, it is used to describe the cessation of life. Second, death refers to an eternal separation from God as a result of sin  This, they teach, is unnatural. When God created Adam and Eve, death was not part of the created order. It was not until they sinned that death entered the scene  They further teach that death will be destroyed when Jesus returns and the believers receive their resurrected bodies.

Many metaphyscians do not use the word 'death'. They believe that there is no actual death, since our consiousness continues on.