synergism

in toxicology
https://doi.org/10.1351/goldbook.S06229
Pharmacological or toxicological interaction in which the combined biological effect of two or more substances is greater than expected on the basis of the simple summation of the @T06414@ of each of the individual substances.
Source:
PAC, 1993, 65, 2003. (Glossary for chemists of terms used in toxicology (IUPAC Recommendations 1993)) on page 2103 [Terms] [Paper]