mean lethal dose: meaning, definition, pronunciation and examples
Very LowTechnical/Scientific
Quick answer
What does “mean lethal dose” mean?
The amount of a substance, such as a drug, chemical, or radiation, that is calculated to be fatal to 50% of a defined population of test organisms (e.
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Pronunciation
Definition
Meaning and Definition
The amount of a substance, such as a drug, chemical, or radiation, that is calculated to be fatal to 50% of a defined population of test organisms (e.g., animals) under specific, controlled conditions.
A statistical measure used in toxicology, pharmacology, and radiology to quantify the acute toxicity of a substance. It is a standardised benchmark for comparing the lethality of different agents, commonly abbreviated as LD50 (Lethal Dose, 50%). It is not a measure of chronic toxicity or non-lethal effects.
Dialectal Variation
British vs American Usage
Differences
No significant differences in meaning or usage. Spelling follows respective conventions (e.g., 'calculated' vs. 'calculated' is not relevant here). The abbreviation LD50 is universal.
Connotations
Purely technical and neutral in both varieties. Carries connotations of laboratory science, risk assessment, and regulatory standards.
Frequency
Extremely rare outside scientific, medical, regulatory, or hazardous materials contexts. Frequency is identical in both dialects within those fields.
Grammar
How to Use “mean lethal dose” in a Sentence
The mean lethal dose (LD50) of [SUBSTANCE] for [ORGANISM] is [NUMBER] [UNITS].Researchers determined the mean lethal dose.A substance with a low mean lethal dose is highly toxic.Vocabulary
Collocations
Examples
Examples of “mean lethal dose” in a Sentence
adjective
British English
- The LD50 value is critical for classification.
- They reviewed the mean lethal dose data.
American English
- The LD50 value is critical for classification.
- They reviewed the mean lethal dose data.
Usage
Meaning in Context
Business
Rare, except in pharmaceutical, chemical, or agrochemical industries for regulatory filings and safety data sheets (SDS).
Academic
Core term in toxicology, pharmacology, ecotoxicology, and related life sciences. Used in research papers, lab reports, and textbooks.
Everyday
Virtually never used. A layperson might say 'a deadly amount' or 'poisonous dose'.
Technical
The primary context. Used in laboratory studies, chemical safety assessments, forensic toxicology, and environmental risk analysis.
Vocabulary
Synonyms of “mean lethal dose”
Strong
Neutral
Weak
Vocabulary
Antonyms of “mean lethal dose”
Watch out
Common Mistakes When Using “mean lethal dose”
- Using it to describe a dose that killed one specific individual (it's a population statistic).
- Using it in non-scientific contexts where 'lethal dose' or 'deadly amount' is more appropriate.
- Confusing it with 'minimum lethal dose' or 'maximum tolerated dose'.
- Pronouncing 'mean' as if it were the adjective meaning 'unkind'.
FAQ
Frequently Asked Questions
No. The LD50 is a population statistic. It means that under specific test conditions, 50% of a group of animals died. It does not predict the exact lethal dose for an individual, as susceptibility varies.
The 50% mortality point (the median) is the most statistically robust and reproducible measure from dose-response experiments. It is less variable than trying to determine the dose that kills the first or last individual in a group.
Human LD50 values are never experimentally determined for ethical reasons. They are estimated by extrapolation from animal data, which has significant limitations. Human toxicity data comes from accidental exposures and case reports.
LD50 (Lethal Dose 50) refers to a dose administered (e.g., mg/kg of body weight). LC50 (Lethal Concentration 50) refers to the concentration of a substance in an environmental medium (e.g., air or water) that is lethal.
The amount of a substance, such as a drug, chemical, or radiation, that is calculated to be fatal to 50% of a defined population of test organisms (e.
Mean lethal dose is usually technical/scientific in register.
Mean lethal dose: in British English it is pronounced /ˌmiːn ˈliːθəl ˈdəʊs/, and in American English it is pronounced /ˌmin ˈliθəl ˈdoʊs/. Tap the audio buttons above to hear it.
Learning
Memory Aids
Mnemonic
Think of 'MEAN' as the average (mathematical mean) 'LETHAL' (deadly) 'DOSE' (amount given). It's the amount that's deadly to half the test subjects on average.
Conceptual Metaphor
A CALIBRATED THRESHOLD OF DEATH. The term conceptualises lethality as a measurable quantity with a precise statistical point (the 50% mark).
Practice
Quiz
What does the 'mean' in 'mean lethal dose' specifically refer to?