Microcosm (noun)

1. A small, representative system that embodies or parallels a larger or more complex system or universe.
2. A miniature representation of the universe or a complex system.

Origin:

From the greek μῑκρος (mikros) meaning "small" and κόσμος (kosmos) meaning "world, universe".

Examples:

1. A city can be seen as a microcosm of the country.
2. A school can be seen as a microcosm of society.
3. The human body is often referred as a microcosm of the universe.
4. The company is a microcosm of the industry.
5. The lake is a microcosm of the ocean.