multiplication
US /ˌmʌl.tə.pləˈkeɪ.ʃən/
UK /ˌmʌl.tə.pləˈkeɪ.ʃən/

1.
2.
an increase in number or quantity
:
•
The rapid multiplication of cells led to the growth of the tissue.
•
We observed a significant multiplication of bacteria in the culture.