Endocytosis, pinocytosis and phagocytosis are means of taking in materials into the cell membrane.
Endocytosis is a cellular process of taking materials by invagination of the cell membrane to form a vacuole.
Pinocytosis is a cellular process of taking materials (mostly liquid) into the cell by budding of small vesicles from the cell membrane.
Phagocytosis is a cellular process of taking materials (foreign bodies such as bacteria) by phagocytes to form a phagosome.
Exocytosis is a cellular process, a form of active transport use to transport materials OUT of a cell.
Endocytosis- General category of allowing molecules in via pockets of the cell membrane. Phagocytosis- Engulfing large particles by extension of the cytoplasm, specifically solid particles. Pinocytosis- Cell membrane folds in and forms a vesicle, takes in molecules like proteins. Exocytosis- Expelling molecules by allowing vacuole with unwanted molecule to connect to membrane and open out of the cell (reverse of Endocytosis).