A box set in music is when an artist publishes several albums and packages them in, aptly enough, a box. Box sets also traditionally contain additional items related to the artist; this could include books, pictures, specially designed cases, DVDs, and more.
If an artist's song catalogue is large enough, the albums in a box set may be a greatest hits compilation. This is rare, though, and box sets typically contain concert performances, previously-recorded but unreleased studio work (see B-sides), or previously-released albums packaged together.
It is uncommon (due to the cost of manufacturing) for an artist to release a box set with all-new studio material.
