民 folk

You can think of "folk" as being a bunch of families who all speak with one mouth, one voice. Usually urging the ethnic cleansing of the other folk. Ethnic strife is MEAN!!

people of a country ★★★☆☆
国 (country) + 民 (folk) = 国民 (people of a country)

the people, as in, "The Republicans are the People's party!"

ethnic ★★★☆☆
民 (folk) + 族 (family) = 民族 (ethnic)

two meanings: 1) ethnic group, 2) folk (as in folk customs, folk music, etc)

citizens of a city ★★☆☆☆
市 (small city) + 民 (folk) = 市民 (citizens of a city)

democracy ★★☆☆☆
民 (folk) + 主 (master/mainly) + 主義 (- ism) = 民主主義 (democracy )