Devil (from the Greek word διαβολοξ (diábolos), which means "one who throws things around" in the sense of creating the chaos, or "slanderer" in the sense of name-calling or "throwing" false accusations), is the name given to the unseen personification of evil.
By causing chaos, the devil leads people away from God and sometimes even to curse God.
During the Three Temptations of Christ, the devil explains how the world is his dominion. This amounts to Biblical scientific foreknowledge, as the world is fundamentally uncertain and chaotic according to quantum mechanics.
The term "devil" is often used synonymously with the term Lucifer or Satan, although Satan has the connotation of a personal evil while the devil is a common name for demons or evil spirits.