(transitive) To add on top of a previous addition.
1843, Thomas_Carlyle, , book 2, ch. IX, Abbot SamsonTo our antiquarian interest in and his Convent, where the whole aspect of existence, the whole dialect, of thought, of speech, of activity, is so obsolete, strange, long-vanished, there now superadds itself a mild glow of human interest for …
2007, Lex Newman The Cambridge companion to Locke's "Essay concerning human understanding"‎Locke's claim that God may superadd to matter a faculty of thinking allows us to usefully relabel our problem. . .
