| Abbreviation | Definition |
|---|---|
| LCSW | Licensed Clinical Social Worker |
| LCT | Loose Connective Tissue |
| LCT | Launch Countdown |
| LCT | Liver Cell Tumor |
| LCTA | Lungs clear to auscultation |
| LCUG | Liquid Cooling Under Garment |
| LCV | Loop Control Variable |
| LCVG | Liquid Cooling and Ventilation Garment |
| LCx | Left Circumflex Artery |
| LD | List Directory |
| LD | List Designs |
| LD | Lethal Dose |
| LD | Logarithm Digitalis |
| LD | Liver Disease |
| LD-50 | Lethal Dose at 50 millirem |
| LD-51 | Lethal Dose resulting in 50% mortality |
| LDA | Low Dose Allergens |
| LDAP | Lightweight Directory Access Protocol |
| LDAR | Leak Detection and Repair |
| LDB | Launch Data Bus |
| LDB | Logistics Data Bank |
| LDC | Lower Division Clerk |
| LDC | Less Developed Country |
| LDC | Least Developed Countries |
| LDC | Lesser Developed Countries |
| LDEC | Lunar Docking Events Controller |
| LDEF | Long Duration Exposure Facility |
| LDH | Lactate Dehydrogenase |
| LDH | Lifetime Drinking History |
| LDI | Load Data Immediate |
| LDIU | Launch Data Interface Unit |
| LDL | Low Density Lipoprotein |
| LDM | Logical Data Model |
| LDMS | Langley Directives Management System |
| LDN | Licensed Dietitian Nutritionist |
| LDO | Local Dental Officer |
| LDOC | Long Distance Operational Control |
| LDP | Lumbo-Dorsal Pain |
| LDPE | Low Density Polyethylene |
| LDPH | Lead Director of Public Health |
| LDQ | Leeds Dependence Questionnaire |
| LDR | Labor Deliver Recovery |
| LDR | Large Deployable Reflector |
| LDR | Land Disposal Restriction |
| LDRP | Labor Delivery Recovery Postpartum |
| LDS | Load Pointer Using DS |
| LDS | Laser Docking Sensor |
| LE | Line Edit |
| LE | Lupus Erythematosus |
| LE | Left Eye, Lower Extremity |