(historical) An ancient city founded by Alexander the Great at the south-western end of the Fergana Valley (modern Tajikistan). It was the northernmost outpost of the Greek Empire in Central Asia.

(organic chemistry) A stereoisomer and pseudoenantiomer of cinchonine, used in asymmetric synthesis

(US, military) Initialism of post exchange. The U.S. Army's Post Exchange. / Abbreviation of peroxidase.

(inorganic chemistry) Any element in the same group as platinum in the periodic table / (inorganic chemistry) Any binary compound of platinum and a more electropositive metal