Phagocytosis [“cell devouring’] — the process in which a phagocyte or a protist engulfs a solid particle a to form an internal phagosome.
Phagocytosis itself is a specific form of endocytosis involving the vesicular internalization of solids such as bacteria. It is distinct from other forms of endocytosis such as the vesicular internalization of various liquids.
Phagocytosis is involved in the acquisition of nutrients for some cells, and, in the immune system, it is a major mechanism used to remove pathogens and cell debris such as bacteria, dead tissue cells, and small mineral particles.
The process is similar to eating only in single-celled organisms. In multicellular animals, the process has been adapted to eliminate debris and pathogens, as opposed to taking in fuel. [ source:Wikipedia ]
This is an illustration not only of a macrophage and its organelles but also outlines how the process of phagocytosis occurs.