1) Separate, apart, perhaps ‘in pieces’ in some cases.
1508 I witt to Thomas my brother my secondary gowne, beying sondre, Ripon
1552 a reed jackett taken sunder and lyinge in quarters, Garforth. As a verb it meant to separate or move apart: c.1620 a workeman ... did Cast some what Iron firth of the harth ... amongst the ... persons soe struggling whereupon they sundred one from another, Bradley, Huddersfield. It occurs several times in the place-name Sunderland: 1274 Matheus de Sundreland, Halifax
1424 ‘dwelling in Sondreland’, Tickhill.