D defs.my
Entry 1 sense Webster, 1913

Additament

/(ăd*dĭt"ȧ*ment)/ · Ad·dit·a·ment · IPA
01 n. An addition, or a thing added.
  1. 1.
    An addition, or a thing added.
    “My persuasion that the latter verses of the chapter were an additament of a later age.” Coleridge.