Baptism means being submerged in water and coming back up. The Greek word is baptidzo. It is used to describe a ship that has sunk and is completely under water.
Christian baptism symbolizes death and resurrection
Buried with Him in baptism, in which you also were raised with Him through faith in the working of God, who raised Him from the dead. (Colossians 2:12)
Therefore we were buried with Him through baptism into death, that just as Christ was raised from the dead by the glory of the Father, even so we also should walk in newness of life. (Romans 6:4)
The idea of death and resurrection refers to leaving the old life of sin and moving into new life in Christ. (Romans 6:11-14)
When you are baptized you make a public declaration, in front of witnesses, that you are stating a new life that you are going in a new direction. It is a decision to change. You are choosing to die to old habits and old ways of thinking and you choose to start a new life according to God’s principles.
Baptism is a public declaration of a decision that you have made. You have chosen to die to your old life and live by God’s principles. You have chosen to wash away old habits and take on new ones. You have chosen to repent of your old ways and start in a new direction. In short, baptism is an outward sign of an inward decision to follow Jesus.