What is death, biblically?
The Bible talks about three different kinds of death. They are all characterized by one thing—separation. Physical death is a separation of the soul from the body. Spiritual death is a separation of the soul from God. Then there is death to sin, separating one from sin and joining him to God.
Most of the time the Bible talks about death it is talking about physical death. People die in battle, of disease or age, or in an accident. The breath leaves the body, the soul is separated from its temporary housing.
The second kind of death is spiritual death, where the soul is separated from God. ““But your iniquities have separated between you and your God, and your sins have hid his face from you, that he will not hear.” (Isaiah 59:2) ” Even when we were dead in sins, hath quickened us together with Christ, (by grace ye are saved;)” (Ephesians 2:5) “And you, being dead in your sins and the uncircumcision of your flesh, hath he quickened together with him, having forgiven you all trespasses.” (Colossians 2:13)
We can also be dead to (or separated from) the sinful way of life. “Who his own self bare our sins in his own body on the tree, that we, being dead to sins, should live unto righteousness: by whose stripes ye were healed.” (1 Peter 2:24) Paul expresses this concept best in Romans 6. There he says that when we are immersed in water for the forgiveness of sins, we rise to walk in new life. In this new life we are dead to sin, but alive to Christ.
These, then are the three basic concepts of death in the Bible. I hope this answers your question.