Wynn
Wynn is a letter in the old English alphabet that came from a rune (ᚹ) by the same name. It was used to represent the sound /w/.
In written Old English and Middle English it was borrowed to represent the same sound, as the letter W was a later invention. It gradually fell out of use as 'uu' (hence "double-U" for our modern "w") and later a merged form 'w' increased in use to represent the /w/ sound.
The rune was held to represent joy, and is the only rune other than þ to have been borrowed into the Latin alphabet.