 It is derived from the Proto-Indo-Iranian term "*witasti-" and is related to Avestan "vītasti", Kurdish "bist" and Persian "bidast", all meaning "span".According to the Vāstuśāstra, a vitasti is equal to 12 aṅgulas.It is defined as the long span between the extended thumb and the little finger or as the distance between the wrist and the fingertips.