a combination of the word MAC and jacket. Associated with the junior rowing team Marina Aquatic Center in Marina del Rey,CA whose uniform consists of wearing a sick red jacket with the letters mac written across.
random rower:why didn't you wear your macket today it's freezing?!
MAC rower: Do you even row for MAC?.....
MAC novice: I haven't gotten my macket yet, all i have is this mac sweatshirt with a retarded hood fml :'(