Guyró

Etymology
From where the -n is lost following nationalisation of the preceding vowel (cf.  > ). The diphthong is due to the -ð- getting a j sound before r, akin to from.

Usage notes
Because the diphthong in this name is identical to the Setesdal pronunciation of long y, is has often been written like Gyro (i.e. ). However, this spelling would imply it’s pronounced with (palatalisation before Old Norse front vowels) and not.