'Red-light district' definitions:

Definition of 'red-light district'

(from WordNet)
noun
A district with many brothels

Definition of 'Red-light district'

From: GCIDE
  • Red-light district \Red-light district\ A district or neighborhood in which houses of prostitution are located; -- so called in allusion to the red light kept in front of many such resorts at night. [Colloq. or Cant] [Webster 1913 Suppl. +PJC]