reversibility

Reversibility refers to the ability of a process to be undone, returning to its original state without any lasting changes. In practical terms, a reversible process can be reversed without loss of energy or matter, meaning if you reverse it, everything goes back exactly as it was. For example, melting ice into water is reversible because you can refreeze the water back into ice without losing any material. In contrast, irreversible processes, like burning paper, change the system permanently. Reversibility helps us understand efficiency and energy flow in physics and engineering.