The story
- Old Norse · derived fromSveins ey
- Middle English · derived fromSweynesse
- English todaySwansea
From Middle English Sweynesse (c. 1165), Sueinesea (1190), Swanesey (1322), from Old Norse Sveins ey (literally “Sveinn’s island”).
Etymology from Wiktionary, CC BY-SA 4.0.