addition Pronunciation: /əˈdɪʃn/Translate addition | into French | into Italian | into Spanish German translation of additionn. 1 Hinzufügen; (adding up) Addieren; (process) Addition in addition = außerdem in addition to = zusätzlich zu 2 (thing added) Ergänzung (to zu) addition in other Oxford dictionaries Definition of addition in the British & World English dictionary Definition of addition in the US English dictionary