Þ, þ is a letter of the Runic alphabet, later adopted in some variants of the Latin alphabet: in Icelandic, in Old and Middle English as well as in earlier stages of the Scandinavian languages. Its English name is thorn [ˈθɔː(ɹ)n]. It was pronounced [θ] or [ð] in English, depending on its position in the word. It is pronounced [θ] in Icelandic.
Use in English
During the Middle English period, þ was replaced progressively by the digraph th, while simultaneously, calligraphy was making þ more and more similar to y. The only remnant of þ in current English is the definite article ye, pronounced [ji] and perceived as an archaic variant of the in commercial or humoristic names such as Ye Olde Shoppe ('The Old Shop'). In fact, this ye [ji] (as opposed to the old accusative ye of you) has never existed, being nothing but an erroneous reading of the old spelling þe for the.