Man is ten thousand or accurately 10000 in Korean culture. Like in Japan it is a natural entity, meaning a word that is not a multiple, the way we think of million in Western culture
To demonstrate its usage in Korean counting:

10 (ship)
100 (paek)
1000 (chon)
10000 (man)
10 0000(ship man)
100 0000(baek man)
1000 0000(chon man)

Until the next mental unit, the ok.

To pronounce man correctly, imagine you are speaking man with a weak Jamaican accent as in, "yeah man."

Man Won
Man won is the largest bill in Korean currency as legal tender. This can be really annoying. Imagine the largest bill being $10. The larger denominations 100,000 and higher are bank cheques meaning you can't use them without showing ID or providing personal details.

Due to inflation, the man won is the common denomination in Korea, and it can cause problems for Koreans in mental conversion to English thousands and millions.1

1For example:
Korean,"The car is i chon man 'on."
-->Korean mental conversion - "the car is two thousand ten thousand won?"
-->"The car is twenty million won."

See ten thousand for more informantion on the significance of 10000