the quantity of a lethal substance, as a poison or pathogen, or of ionizing radiation that will kill 50 percent of the organisms subjected to it in a specified time period. Symbol: LD 5 0.
the amount of a drug or other substance that, when administered to a group of experimental animals, will kill 50 per cent of the group in a specified time
the amount of ionizing radiation that will kill 50 per cent of a population in a specified time
- Median line
median line n.
- Median longitudinal raphe of tongue
median longitudinal raphe of tongue n. See median groove of tongue.
- Median nerve
median nerve n. A nerve that is formed by the union of the medial and lateral roots from the medial and lateral cords of the brachial plexus and supplies the muscular branches in the anterior region of the forearm and the muscular and cutaneous branches in the hand.
noun, Anatomy. 1. a vertical plane that divides an organism into symmetrical halves. median plane n. A vertical plane along the midline of the body dividing the body into right and left halves. Also called midsagittal plane.