superaddition

noun

su·​per·​ad·​di·​tion ˌsü-pər-ə-ˈdi-shən 

-a-ˈdi-

plural superadditions

: the act or process of superadding something

… he saw that it was a long quadrangular structure of brick … with the ornamental superaddition of an octagonal tower …

—Joseph Holt Ingraham

There may be certain states existing which are highly favourable to the propagation of disease, yet until the superaddition of some other element entering into the causation, the specific poison might not come into full operation …

—John Richard Wardell

Word History

First Known Use

1610, in the meaning defined above