LD
abbreviation
1- lethal dose (of a toxic compound, drug, or pathogen). It is usually written with a following numeral indicating the percentage of a group of animals or cultured cells or micro-organisms killed by such a dose, typically standardized at 50 per cent (LD50).（有毒化合物, 药物, 病原体的）致死剂量（其后通常接一数字指明该剂量杀死一组动物、培养细胞或微生物的百分比, 常规标准为50％）。
1.1
- N. Amer. learning disability (or disabled)〈北美〉同LEARNING DISABILITY(或learning disabled)。