Mastered is a term used in the music and audio industries. It is usually a song that is in or at its final stage before mass production or sells.
A mastered song is a single stereo track that has been finalized by a mastering engineer who uses his skills, technique and gear to bring the life out of a mix. Fatten it up, making it full and thick at the same time bringing out certain parts in the mix. example - vocals.
hey be sure the mix has at least 3dB of headroom before we send it out to get mastered. He will bitch if has no headroom to work with