APA Dictionary of Psychology

n. the process by which bacteria, viruses, nutrients, other cells, and cell debris are engulfed by cells called phagocytes. The substances are first surrounded by a membrane, forming a vacuole within the phagocyte. The vacuole then fuses with a lysosome, an organelle containing enzymes that digest the engulfed contents. Certain white blood cells act as phagocytes as part of the immune response.