The first name Olwyn is of Arthurian Legend, Celtic, Welsh origin. It is often a girl name. It has the following meaning(s):
Arthurian Legend: Daughter of a Giant
Celtic: Mythical Daughter of Yspaddaden
Welsh: Variant of Olwen: White Footprint. in 'Culhwch and Olwen', One of the Welsh Stories from the 'Maginogion', the Olwen Were White Flowers Growing in the Heroine's Footprints