The Collaborative International Dictionary
Additament
Additament \Ad*dit"a*ment\ ([a^]d*d[i^]t"[.a]*ment), n. [L.
additamentum, fr. additus, p. p. of addere to add.]
An addition, or a thing added.
--Fuller.
My persuasion that the latter verses of the chapter
were an additament of a later age.
--Coleridge.
Wiktionary
additament
n. An addition, or a thing added. ''Fuller''.