ad·dit·a·ment \əˈdid.əmənt, aˈ-\noun (-s) Etymology: Middle English, from Latin additamentum, from additus (past participle of addere to add) + connective -a- + -mentum -ment — more at add : a thing added : addition < the latter verses of the chapter were an additament of a later age — S.T.Coleridge >