Connotation—What death really means
Many people view death as a tragedy, often because they believe the person has been annihilated or that at least they'll not see them again, but Mormons, while they mourn for the loss of their loved one, view death in a different light. Wilford Woodruff, a great LDS prophet, said, "A great many believe that when a man dies that is the end of him, that there is no hereafter. Can any sensible man believe that the God of heaven has created two or three hundred thousand million spirits, and given them tabernacles [physical bodies], merely to come and live upon the earth and then to pass away into oblivion and to be annihilated? It seems to me that no reflecting man can entertain such belief. It is contrary to common sense and to serious reflection." So while Mormons sorrow for the loss of companionship of their loved one, they are consoled that the one lost in death has made a "gain, for it is the march of progress, advancement and development." Death to Mormons means separation from one state and transition to another—from death in the pre-mortal state to birth in the mortal state, and likewise, from death in the mortal state to birth in the immortal state. They also believe that the hereafter is better than here, the place of trials and tests, particularly if people have lived up to their understanding of what is right. "If mortality be the perfect state, then death would be a frustration, but the gospel teaches us that there is no tragedy in death, but only in sin ("Blessed are the dead that die in the Lord" D&C 63:49). Seen in that light Mormons find it impossible to grieve for people who have died, for they have left a world of adversity and sorrow and entered a happier place and condition. To Mormons, to grieve that people have died would be like grieving because they have graduated from college, leaving the stress of studies, tests, and scrimping behind them. In addition, Mormons believe that their relationships with the "departed" may continue in the hereafter because family members may be sealed to each other eternally. Other relationships may also continue.
Introduction of Physical Death to Earth
Mormons believe that death first came to the world through the Fall of Adam ("For as in Adam all die, even so in Christ shall all be made alive" 1 Cor. 15:21-23), and that the Resurrection from death comes through the Savior's Atonement. In addition they believe that there is only one physical death because after people die they are resurrected and can die no more (Alma 11:42-45). Death is part of the gospel plan, and so should not be dreaded or feared.