Macrocosm means great, universal, a complex that represents on a large scale one of its components: “The painter has drawn the picture of a man’s body with a macrocosm of heart showing its atria walls and veins bigger than the original ones.”
Microcosm , on the other hand, means small, little, representing the epitome of a larger entity: “The play, being the imitation of life, represented the microcosm of the problems and complexities faced by man.”