The main difference between autophagy and phagocytosis is that autophagy occurs when lysosomes are fused with autophagosomes in order to digest the dysfunctional structures of the cell taken into autophagosomes whereas phagocytosis occurs when a foreign substance is engulfed by the cell, forming a vacuole called phagosome, surrounding the foreign substance in order to separate it from the cytoplasm.

(출처 : https://www.researchgate.net/post/What-is-the-difference-between-Autophagy-and-Phagocytosis#:~:text=the%20foreign%20substance.-,The%20main%20difference%20between%20autophagy%20and%20phagocytosis%20is%20that%20autophagy,cell%2C%20forming%20a%20vacuole%20called)

phagocytosis 은 외부물질을 endocytosis으로 engulf 해서 생긴 food vacuole에 lysosome이 fuse 해서 digestion 하는 과정을 의미
autophagy는 malfunction 하는 cell 안의 organelle 주위로 vesicle 이 생겨서 그 vesicle 이랑lysosome이 fuse 해서 digestion 하는 과정을 의미