the people; the masses; multitude
Archaic or highly literary term for the common people or a vast multitude. In modern Japanese, 民衆 or 大衆 are far more common.
In classical texts, it is sometimes used as in 'the vast multitude of people'.
Compound of 億 (hundred million) and 兆 (trillion), originally meaning an extremely large number, later extended metaphorically to 'the vast multitude of people'. The exact historical derivation is uncertain.