Reversible process

A reversible process is a process that can be reversed through tiny changes, without a dissipation of energy. This is a useful concept in thermodynamics.

Alternatively, a reversible process is one that can be reversed without changing the system or its surroundings.

An example of an irreversible process is the puncturing of a car tire. It is impossible to put the air back in the tire and patch it up without dissipating energy or changing the tire and the surroundings.