| 8512 | D.M.D. (doctor of medical dentistry) | |
| 1520 | Dairy (except fluid milk) | |
| 5520 | Dairy bars-retail | |
| 1533 | Dairy cattle feeds, supplements, concentrates and premixes, manufacturing | |
| 5121 | Dairy cattle, wholesale | |
| 0121 | Dairy cows and milk, producing | |
| 5122 | Dairy depots, wholesale | |
| 2921 | Dairy farm machinery and equipment, manufacturing | |
| 5150 | Dairy farm machinery and equipment, wholesale | |
| 5150 | Dairy farm machinery, wholesale | |
| 0121 | Dairy farming | |
| 0121 | Dairy heifer replacement production | |
| 7421 | Dairy herd consulting services | |
| 0140 | Dairy herd improvement associations | |
| 5122 | Dairy products (except dried or canned), wholesale | |
| 5150 | Dairy products manufacturing machinery, wholesale | |
| 5220 | Dairy products stores, retail | |
| 5122 | Dairy products, canned or dried, wholesale | |
| 5122 | Dairy products, frozen, wholesale | |
| 5259 | Dairy products, house-to-house, retail | |
| 5122 | Dairy products, processed (except canned), wholesale | |
| 5110 | Dairy products, wholesale agents and brokers | |
| 5520 | Dairy queen | |
| 5150 | Dairy supplies, wholesale | |
| 1520 | Dairy, fluid milk | |
| 4520 | Dam construction, general contractors | |
| 2811 | Dam gates, metal plate, manufacturing | |
| 7514 | Damage claims (non-commercial), federal | |
| 1711 | Damask fabrics, broad-woven, weaving | |
| 3312 | Damper operators (e.g., electric, pneumatic, thermostatic), manufacturing | |
| 2811 | Dampers, sheet metal, manufacturing | |
| 4530 | Dampproofing buildings, contractors | |
| 4530 | Dampproofing, concrete | |
| 4520 | Dams, hydroelectric power, construction | |
| 9214 | Dance bands | |
| 9214 | Dance companies | |
| 9214 | Dance festival promoters, with facilities | |
| 9214 | Dance festival promoters, without facilities | |
| 7010 | Dance hall rental or leasing | |
| 9219 | Dance halls | |