irreversibility

Irreversibility refers to processes that cannot simply be undone or reversed to restore the original state. For example, when you breaking a glass or burning paper, the changes are permanent—rebuilding the glass or reversing combustion isn't practically possible. In thermodynamics, it describes how systems naturally tend to move toward disorder or higher entropy, making certain changes effectively one-way. This concept helps explain why some processes, like mixing milk into coffee, are difficult or impossible to reverse exactly as they were. Essentially, irreversibility highlights the natural tendency of systems to evolve toward more probable, less ordered states.