Macau Association of Composers, Authors and Publishers (MACA) is a collection society that provides licenses and authorization for the use of works of its members, collects royalties and distributes these royalties to its members. MACA represents 91 local members and six local publishers, as well as over two million music creators from the 49 affiliated societies holding reciprocal agreements with MACA as of January 2018.
Music Publishing is the business of protecting and promoting song copyrights and collecting the royalties that these copyrights generate. Think of a song as intellectual property (it's an original piece of art!), and music publishing as the business that makes sure that songwriters get paid a fair compensation when their intellectual property is used by companies. Those companies could be record labels (mechanical royalties), radio stations, bars, and restaurants (performance royalties), or film studios and advertising agencies (sync license fees), and many more.