A / addĭtĭo
noun

addĭtĭo

gen. addĭtōnis · gender feminine · decl. 3rd
an adding to; addition
an adding to, addition: figurarum additio et abjectio, Quint. 9, 3, 18: Sic corpori fit additio, Cael. Aur. Acut. 2, 37; Prisc. p. 978 P.