| D4C | Dirty Deeds Done Dirt Cheap 
| Others |
| D4C | Driving for Change
| Others |
| D4D | Direct for Diesel
| Others |
| D4D | Drive for Diversity
| Others |
| D4H | Decisions 4 Heroes
| Others |
| D4L | Drive for Life
| Others |
| D4P | Double Four Patch
| Others |
| D4Q | Digital For Quality
| Others |
| D4S | Direct Injection Four Stroke Superior Version
| Others |
| d4T | stavudine
| Others |
| d4T | tavudine
| Others |
| D4W | Down for Whatever
| Others |
| D4X | Download Manager for X
| Others |
| D5 | 5% Dextrose
| Others |
| D5 | Destructive-size scale
| Others |
| D5 | Fifth Coast Guard District
| Others |
| D5 1/2NS | Dextrose 5% in 0.45% sodium chloride injection
| Others |
| D5% | Dextrose 5%
| Others |
| D5%DW | Dextrose 5% in distilled water
| Others |
| D5%NS | Dextrose 5% in normal saline
| Others |
| D50 | 50% Dextrose injection
| Others |
| D56 | Mayville Municipal Airport, Mayville, North Dakota USA
| Others |
| D5LR | Dextrose 5% in Lactated Ringer's injection
| Others |
| D5NS | 5% Dextrose in Normal Saline solution
| Others |
| D5NS | Dextrose 5% in Normal Saline (0.9%)
| Others |
| D5Q | De 5 Quality
| Others |
| D5W | 5% Dextrose in Water injection
| Others |
| D5W | 5% Dextrose in Water solution
| Others |
| D5W | Dextrose 5% in Water
| Others |
| D5W | Dextrose 5% Solution in Water
| Others |
| D6 | 6-Sided Dice
| Others |
| D63 | Commodore 64 emulator disk file
| Others |
| D6D | Decide
| Others |
| D7 | Seventh Coast Guard District
| Others |
| D79 | Dart Airport, Mayville, New York USA
| Others |
| D8 | 8-Sided Dice
| Others |
| D8 | Date
| Others |
| D8 | Eighth Coast Guard District
| Others |
| D80DV | Descendants of the 80th Division Veterans
| Others |
| D87 | Harbor Springs Airport, Harbor Springs, Michigan USA
| Others |
| D9 | Divine Nine
| Others |
| D9 | Ninth Coast Guard District
| Others |
| D:-O | Hats off to you!
| Others |
| D:? | Confusion and Sadness at the same time
| Others |
| DA | A Defence Army
| Others |
| Da | Aerospace Drift
| Others |
| DA | Antiseptic vs. Disinfectant
| Others |
| DA | Dad's Army
| Others |
| DA | Dads Army
| Others |
| DA | Dagga Allowed
| Others |