The thermodynamic limit refers to the behavior of a system as the number of particles and the volume approach infinity. In this limit, the properties of the system become independent of the size, allowing for the simplification of calculations in statistical mechanics. This concept is crucial for understanding phase transitions and critical phenomena in materials. In practical terms, the thermodynamic limit helps scientists and engineers predict how large systems behave based on the average properties of smaller samples. It is essential for theories involving phase transitions, critical points, and the overall behavior of gases, liquids, and solids in thermodynamics.