What does the word ghetto mean and where does it come from?

In the Middle Ages and later a ghetto (pronounced ge-to) was a walled in area where Jews were forced to live, by law. It was locked at night, and Jews had to make sure that they were back inside the ghetto before the curfew.
There are various theories about the origins of the word. One of the more popular suggestions is that it is derived from Italian borghetto - which means little town or little borough. The first use of the word dates from about 1600 in Venice.
In Europe the last ghetto to be opened and dissolved was that in Rome, which was opened in 1870 when Italian nationalist forces took the city. They had no time for reactionary, Roman Catholic 'churchy nonsense', which is how they saw the ghetto.
However, in 1939-41 the Nazis revived ghettos, especially in Poland and Lithuania.
From the 1960s onwards the term was applied figuratively to the run down inner city areas of American cities.