A stack of flattened vesicles that functions in the post-translational processing and sorting of proteins. The Golgi receives proteins from the rough endoplasmic reticulum (RER) and directs them to secretory vesicles, lysosomes or the cell's plasma membrane. The movement of the proteins takes place by transfer vesicles that bud off from the RER or Golgi and fuse with the Golgi, lysosomes or plasma membrane. The surface of the Golgi that faces the RER is termed the cis-Golgi, the surface towards the apical membrane is the trans-Golgi, and the intermediary part is the medial Golgi.