Collective Adjectives
When the definite article, the, is combined with an adjective describing a class or group of people, the resulting phrase can act as a noun: the poor, the rich, the oppressed, the homeless, the lonely, the unlettered, the unwashed, the gathered, the dear departed. The difference between a Collective Noun (which is usually regarded as singular but which can be plural in certain contexts) and a collective adjective is that the latter is always plural and requires a plural verb:
• The rural poor have been ignored by the media.
• The rich of Connecticut are responsible.
• The elderly are beginning to demand their rights.
• The young at heart are always a joy to be around.