The
state which a
song is in when it has been
played and
assembled entirely within the confines of a small room designed
precisely for the purposes of
eliminating every
natural noise from the
vicinity with the
exception of the
musical instruments, which no longer sound quite
natural, either.
The term is still applicable to a song which has had several different recordings of a particular instrument, such as guitar or voice, layered one over another to make it sound like the song has that many more instruments.