what is the symbol for parts per thousand
Per mille A per mille[1][2][3] (from Latin per mÄ«lle, "in each thousand"[4]), also spelled per mil,[1][2][4][5][6][7][excessive citations] per mill,[4][5][6][7][8][9][excessive citations] permil,[4] permill,[4] or permille[3] is a sign indicating parts per thousand. Per mil should not be confused with parts per million (ppm).
Infinity symbol The shape of a sideways figure eight has a long pedigree; for instance, it appears in the cross of Saint Boniface, wrapped around the bars of a Latin cross.[1] However, John Wallis is credited with introducing the infinity symbol with its mathematical meaning in 1655, in his De sectionibus conicis.[1][2][3][4] Wallis did not explain his choice of this symbol, but it has been conjectured to be a variant form of a Roman numeral for 1,000 (originally CIƆ, also CƆ), which was sometimes used to mean "many", or of the Greek letter ω (omega), the last letter in the Greek alphabet.[5]