The word ghetto comes from "Ghetto" neighborhood located northwest of Venice, a place where there was a factory dedicated to the iron foundry (from the Latin word meaning ghetto), and where Jews were forced to live since 1516 , when they arrived, expelled from Spain. There the inhabitants residing protective custody and Christian, in gated communities, preventing the freedom to come and go as they wished.
In the year 1555 Pope Paul IV, founded the Ghetto of Rome, being an example to create other, where the Jewish population was discriminated against and confined to living exclusively on them.
Just got under Napoleonic rule in 1797, the free entry and exit of the ghettos, being fully released when the Italian state was formed.
At the dawn of World War II, Adolf Hitler reinstalled these gated communities or ghettos to confine Jews in inhuman conditions, only to be sent from there to the death camps. Among them we can mention the Warsaw Ghetto, the larger, located in Poland that existed for three years, with nearly 400,000 passengers, with exponent of poverty, disease and overcrowding, which caused an uprising of its inhabitants, bloodily repressed.
With this background, the word ghetto came to name any place where he resided only a minority of the population, segregated by their social, racial or religious.
In the U.S. there are among others, Chinatown or black neighborhood, which can be called ghettos with cultural characteristics, which is sometimes synonymous with pride for its residents.