What's the difference between "macrocosm" and "microcosm"

What's the difference between "macrocosm" and "microcosm"? I've done some sleuthing on some online dictionaries to make sense of these words, but I fail to see the difference.

Take Dictionary.com, for example:

MACROCOSM:
Definitions:
1) The entire world; the universe.; the great world or universe; the universe considered as a whole (opposed to microcosm).
(Expanded version: the whole of a complex structure, especially the world or the universe, contrasted with a small or representative part of it. Contrasted with microcosm.)
2) the total or entire complex structure of something; A system reflecting on a large scale one of its component systems or parts.
Example: the macrocosm of war.
3) a representation of a smaller unit or entity by a larger one, presumably of a similar structure.

MICROCOSM:

1) a little world; a world in miniature (opposed to macrocosm)
(expanded version: A small, representative system having analogies to a larger system in constitution, configuration, or development: example: "He sees the auto industry as a microcosm of the U.S. itself" (William J. Hampton).).
Examples: Little Tokyo is a microcosm of Japan.
The dynamic acts as a microcosm for Edinburgh's own theological development
2) anything that is regarded as a world in miniature.
3) human beings, humanity, society, or the like, viewed as an epitome or miniature of the world or universe.