threshold

synonyms: threshold concentration, threshold dose
https://doi.org/10.1351/goldbook.16136
Dose or exposure concentration below which a defined effect will not occur.
See also: critical effect
Source:
PAC, 2007, 79, 1153. (Glossary of terms used in toxicology, 2nd edition (IUPAC Recommendations 2007)) on page 1321 [Terms] [Paper]