sixth column: Meaning and Definition of

sixth' col'umn

Pronunciation: [key]
  1. the persons residing in a country at war who are devoted to aiding the fifth column in its activities, esp. by lowering morale, spreading rumors, etc.
  2. the persons residing in a country at war who are devoted to blocking the efforts of the fifth column.
Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease.