Edh is a character in the Anglo-Saxon and Icelandic alphabets. It looks similar to the numeral 6 with a y-like branch.
It has the sound TH as in THEM.
In fact "y" is often substituted for it on gravestones and quaint store signs: "ye olde candies shoppe" should be read as "THe olde....", although it is jocularly pronounced "yee".