Mastering is the final step in track production, making sure the music sounds appropriate throughout all playback systems

https://pipewiki.org/wiki/index.php/Clipping_Explained:_Avoiding_Common_Pitfalls_in_Mixing_and_Mastering

Mastering is the remaining step in tune creation, ensuring the song sounds satisfactory across all playback procedures. It contains equalization, compression, and limiting to in achieving highest loudness and clarity devoid of shedding dynamics.