Dilyn is of Welsh origin, derived from the word 'dylan,' which means 'like the sea.' It is often used as a boy's name but can also be given to girls.
"The name Dilyn experienced varying popularity over the years, with a notable spike from 1999 to 2004, peaking at 25 births in 2001 and 2004. After 2007, its usage declined, with fewer than 15 births per year."