The spelling of the word "thred" may seem unusual, but it is actually a phonetic variation of the word "thread." In IPA phonetic transcription, the word is pronounced as /θrɛd/, with the "th" representing a voiceless dental fricative sound and the "e" being pronounced as a short "eh" vowel sound. The spelling of "thred" may be seen in certain dialects or accents, but it is important to bear in mind that the proper and widely accepted spelling is "thread."
The word "thred" is a variant spelling of the word "thread", which refers to a thin strand of a fiber like cotton, silk, or nylon, commonly used in sewing or knitting. The etymology of "thread" can be traced back to the Old English word "þrǽd", which is related to the Old Frisian word "thred" and the Old High German word "drat". These words all ultimately derive from the Proto-Germanic word "*þredą". The Proto-Germanic root "*þredą" has Indo-European origins and is believed to have evolved from the Proto-Indo-European root "*tere-", meaning "cross over" or "penetrate". The word "thread" has been a part of the English language since the Old English period and has remained in usage with its spelling adapted to the current "thread" form.