| 1. audibility |  | 48. Automatic radar plotting aids (ARPA) |
| 2. audibility threshold | | 49. automatic range measurement |
| 3. audio frequency | | 50. automatic relative plotter |
| 4. auger | | 51. automatic remote control system |
| 5. augment | | 52. automatic request for repeats |
| 6. augment of resistance | | 53. automatic sound buoy |
| 7. augmentation | | 54. automatic sound signal |
| 8. augmentation of semidiameter | | 55. automatic sprinkler |
| 9. AUM | | 56. automatic start valve |
| 10. aural signal | | 57. automatic steerer |
| 11. aurora | | 58. automatic steerer stabilizer |
| 12. aurora australis | | 59. automatic steering |
| 13. aurora borealis | | 60. automatic tide gauge |
| 14. aurora glory | | 61. automatic tracking |
| 15. aurora polaris | | 62. automatic weather station |
| 16. auroral clouds | | 63. automatic welding |
| 17. auroral display | | 64. Automation |
| 18. austral | | 65. automatization |
| 19. authority | | 66. Automooring systems |
| 20. authority to sign | | 67. autonomous port |
| 21. auto ferry | | 68. autopilot |
| 22. auto radar pilot | | 69. autopilot computer |
| 23. auto-alarm | | 70. autopilot settings |
| 24. auto-alarm receiver | | 71. autumn albacore |
| 25. auto-alarm sender | | 72. autumnal equinox |
| 26. Auto-ignition | | 73. aux. |
| 27. auto-lathe | | 74. auxiliaries |
| 28. autoclave pressure bag molding | | 75. auxiliary |
| 29. autogenous welding | | 76. auxiliary aircraft transport |
| 30. autographic instrument | | 77. Auxiliary blowers |
| 31. Automated Broker Interface (ABI) | | 78. auxiliary boiler |
| 32. automated class | | 79. auxiliary condenser |
| 33. Automated Clearinghouse | | 80. auxiliary contact |
| 34. Automated Export Reporting Pro | | 81. auxiliary craft |
| 35. Automated Trade Locator Assist | | 82. auxiliary cruiser |
| 36. automatic | | 83. auxiliary engine |
| 37. automatic alarm receiver | | 84. auxiliary machinery |
| 38. automatic block control | | 85. auxiliary mine sweeper |
| 39. automatic control | | 86. auxiliary motor yacht |
| 40. automatic control system | | 87. auxiliary powered vessel |
| 41. automatic data processing | | 88. Auxiliary Propulsion Drive |
| 42. automatic direction finder | | 89. auxiliary rudder head |
| 43. automatic helmsman | | 90. auxiliary sailing vessel |
| 44. Automatic Identification System | | 91. auxiliary tank |
| 45. automatic inboard vent tank | | 92. auxiliary vessel |
| 46. automatic keying device | | 93. auxiliary yacht |
| 47. automatic pilot | |
