In the Bible, it refers to ‘wholeness’ in the deepest and most comprehensive sense, i.e. finding our proper place, our true selves, in Christ, ‘coming to the place where we ought to be’.
It means for us as individuals the freedom of sins forgiven and a real hope of eternal life. But more than that, it means the restoration of the whole created order to the place where it ought to be.
Salvation represents to ultimate and absolute restoration of the relationship between God and humankind. If you recall the creation narratives in Genesis 1-2 recall how we were created in relation with God, and turned away and went our own way. From that point the spiritual aspiration of human kind has been to restore that which we have lost. The Incarnation, Crucifixion and Resurrection mean that in Christ Divinity has been carried in our humanity in order that we may follow Christ who has carried our humanity into divinity, and we have been saved from the consequences of our own actions.