1. fifth column a subversive group that supports the enemy and engages in espionage or sabotage; an enemy in your midst
  2. forthcoming at ease in talking to others
  3. support column a column that supports a heavy weight
  4. fifth columnist a member of a clandestine subversive organization who tries to help a potential invader
  5. vertical fin a stabilizer that is part of the vertical tail structure of an airplane
  6. vertebral column the series of vertebrae forming the axis of the skeleton and protecting the spinal cord
  7. vertical union a labor union that admits all workers in a given industry irrespective of their craft
  8. curriculum an integrated course of academic studies
  9. diverticulum a herniation through the muscular wall of a tubular organ
  10. reticulum any fine network
  11. fourth stomach the fourth compartment of the stomach of a ruminant
  12. word class one of the traditional categories of words intended to reflect their functions in a grammatical context
  13. fruticulose of or relating to or resembling a shrub
  14. vertical at right angles to the plane of the horizon or a base line
  15. Fourth Crusade a Crusade from 1202 to 1204 that was diverted into a battle for Constantinople and failed to recapture Jerusalem
  16. Reticulum a small constellation in the southern hemisphere near Dorado and Hydrus
  17. lally column support column consisting of a steel cylinder filled with concrete
  18. North Carolinian a native or resident of North Carolina
  19. agony column a newspaper column devoted to personal problems
  20. hard clam an edible American clam