Per Dictionary.com -
ghet-to
1. a section of a city, esp. a thickly populated slum area, inhabited predominantly by members of an ethnic or other minority group, often as a result of social or economic restrictions, pressures, or hardships.
2. (formerly, in most European countries) a section of a city in which all Jews were required to live.
3. a section predominantly inhabited by Jews.
4. any mode of living, working, etc., that results from stereotyping or biased treatment: job ghettos for women; ghettos for the elderly.
Origin:
160515; < It, orig. the name of an island near Venice where Jews were forced to reside in the 16th century < Venetian, lit., foundry for artillery (giving the island its name), n. deriv. of ghettare to throw < VL *jectāre; see JET 1
But you didn't use urbandictionary.com... you would get a different definition.