- the amount of a drug or other agent that if administered to an animal or human will prove fatalAbbreviation: LD See also median lethal dose (def. 1)
- The dose of a chemical or biological preparation that is likely to cause death.
The American Heritage® Stedman's Medical Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Company. Published by Houghton Mifflin Company.