Universal Decimal Classification

  1. War operations in general. Tactics. Strategy. Theatre of war. History of campaigns
  2. Washing. Laundry. Cleaning
  3. Water for beverages and other industrial uses. Mineral waters. Medicinal waters. Edible ice
  4. Water sampling and analysis
  5. Water sports. Aerial sports
  6. Water supply. Water treatment. Water consumption
  7. Watercraft engineering. Marine engineering. Boats. Ships. Boatbuilding and shipbuilding
  8. Watercraft sports. Boating
  9. West African states and territories narrowly
  10. West Germanic languages (other than English)
  11. West Germanic languages (other than English)
  12. West Germanic literatures (other than English)
  13. West Slavic / Slavonic languages
  14. West Slavic / Slavonic literatures
  15. West Slavic languages
  16. West. Western
  17. Western Church. Western Christianity
  18. Western group of Turkic languages
  19. Western Iranian languages
  20. Western New Guinean languages
  21. Wheel sports. Cycling. Roller sports
  22. Wine. Winemaking. Oenology
  23. Winter sports. Ice games. Skiing. Sledging
  24. Woody climbers (e.g. ivy - Araliaceae)
  25. Work and fatigue. Efficiency
  26. Work science (work studies) in forestry. Harvesting of wood: logging and transport. Forest engineering
  27. Work. Weight. Mass. Friction. Passive resistance
  28. Working conditions other than pay
  29. Working environment. Workplace design. Occupational safety. Hygiene at work. Accidents at work
  30. Working or machining with chip formation. Abrasive working. Hammers and presses
  31. Working with gases
  32. Working with liquids
  33. Worship broadly. Cult. Rites and ceremonies
  34. Writing inks
  35. Writing materials and equipment
  36. Writing systems and scripts
  37. Writing systems. Graphic representations of concepts