"Blend of Jo and Lynn"
The name Joelynn is commonly a female name from the "English" origin.
Joelynn is a modern American formation made by joining Jo, a short form of names such as Josephine, Joanna and Joanne, with Lynn, an element that became frequent in American girls' names in the twentieth century. The two parts also appear written separately as Jo Lynn or with a hyphen, and the one-word spelling here treats the pair as a single given name. There is no older documented name with this spelling to point to.
The pronunciation of Joelynn is JOE-lin.